diff --git a/fs/fs.go b/fs/fs.go
index 0cd95434..345aa002 100644
--- a/fs/fs.go
+++ b/fs/fs.go
@@ -25,6 +25,7 @@ import (
 	"net/http"
 	"os"
 	"path"
+	"sort"
 	"strings"
 	"time"
 )
@@ -40,6 +41,7 @@ type file struct {
 
 type statikFS struct {
 	files map[string]file
+	dirs  map[string][]string
 }
 
 // Register registers zip contents data, later used to initialize
@@ -59,7 +61,8 @@ func New() (http.FileSystem, error) {
 		return nil, err
 	}
 	files := make(map[string]file, len(zipReader.File))
-	fs := &statikFS{files: files}
+	dirs := make(map[string][]string)
+	fs := &statikFS{files: files, dirs: dirs}
 	for _, zipFile := range zipReader.File {
 		fi := zipFile.FileInfo()
 		f := file{FileInfo: fi, fs: fs}
@@ -69,12 +72,26 @@ func New() (http.FileSystem, error) {
 		}
 		files["/"+zipFile.Name] = f
 	}
+	for fn := range files {
+		// go up directories recursively in order to care deep directory
+		for dn := path.Dir(fn); dn != fn; {
+			if _, ok := files[dn]; !ok {
+				files[dn] = file{FileInfo: dirInfo{dn}, fs: fs}
+			} else {
+				break
+			}
+			fn, dn = dn, path.Dir(dn)
+		}
+	}
 	for fn := range files {
 		dn := path.Dir(fn)
-		if _, ok := files[dn]; !ok {
-			files[dn] = file{FileInfo: dirInfo{dn}, fs: fs}
+		if fn != dn {
+			fs.dirs[dn] = append(fs.dirs[dn], path.Base(fn))
 		}
 	}
+	for _, s := range fs.dirs {
+		sort.Strings(s)
+	}
 	return fs, nil
 }
 
@@ -84,7 +101,7 @@ type dirInfo struct {
 	name string
 }
 
-func (di dirInfo) Name() string       { return di.name }
+func (di dirInfo) Name() string       { return path.Base(di.name) }
 func (di dirInfo) Size() int64        { return 0 }
 func (di dirInfo) Mode() os.FileMode  { return 0755 | os.ModeDir }
 func (di dirInfo) ModTime() time.Time { return time.Time{} }
@@ -126,6 +143,7 @@ type httpFile struct {
 
 	reader *bytes.Reader
 	isDir  bool
+	dirIdx int
 }
 
 // Read reads bytes into p, returns the number of read bytes.
@@ -158,12 +176,38 @@ func (f *httpFile) Readdir(count int) ([]os.FileInfo, error) {
 	if !f.isDir {
 		return fis, nil
 	}
-	prefix := f.Name()
-	for fn, f := range f.file.fs.files {
-		if strings.HasPrefix(fn, prefix) && len(fn) > len(prefix) {
-			fis = append(fis, f.FileInfo)
-		}
+	di, ok := f.FileInfo.(dirInfo)
+	if !ok {
+		return nil, fmt.Errorf("failed to read directory: %q", f.Name())
+	}
+
+	// If count is positive, the specified number of files will be returned,
+	// and if negative, all remaining files will be returned.
+	// The reading position of which file is returned is held in dirIndex.
+	fnames := f.file.fs.dirs[di.name]
+	flen := len(fnames)
+
+	// If dirIdx reaches the end and the count is a positive value,
+	// an io.EOF error is returned.
+	// In other cases, no error will be returned even if, for example,
+	// you specified more counts than the number of remaining files.
+	start := f.dirIdx
+	if start >= flen && count > 0 {
+		return fis, io.EOF
+	}
+	var end int
+	if count < 0 {
+		end = flen
+	} else {
+		end = start + count
+	}
+	if end > flen {
+		end = flen
+	}
+	for i := start; i < end; i++ {
+		fis = append(fis, f.file.fs.files[path.Join(di.name, fnames[i])].FileInfo)
 	}
+	f.dirIdx += len(fis)
 	return fis, nil
 }
 
diff --git a/fs/fs_test.go b/fs/fs_test.go
index 7bea8349..36148db3 100644
--- a/fs/fs_test.go
+++ b/fs/fs_test.go
@@ -16,10 +16,13 @@ package fs
 import (
 	"archive/zip"
 	"bytes"
+	"io"
 	"io/ioutil"
 	"os"
+	"path"
 	"path/filepath"
 	"reflect"
+	"sort"
 	"strings"
 	"sync"
 	"testing"
@@ -41,6 +44,8 @@ func TestOpen(t *testing.T) {
 	pixelGifHeader := mustFileHeader("../testdata/image/pixel.gif")
 	indexHTMLHeader := mustFileHeader("../testdata/index/index.html")
 	subdirIndexHTMLHeader := mustFileHeader("../testdata/index/sub_dir/index.html")
+	deepAHTMLHeader := mustFileHeader("../testdata/deep/a")
+	deepCHTMLHeader := mustFileHeader("../testdata/deep/aa/bb/c")
 	tests := []struct {
 		description string
 		zipData     string
@@ -115,6 +120,43 @@ func TestOpen(t *testing.T) {
 				},
 			},
 		},
+		{
+			description: "listed all sub directories in deep directory",
+			zipData:     mustZipTree("../testdata/deep"),
+			wantFiles: map[string]wantFile{
+				"/a": {
+					data:    mustReadFile("../testdata/deep/a"),
+					isDir:   false,
+					modTime: deepAHTMLHeader.ModTime(),
+					mode:    deepAHTMLHeader.Mode(),
+					name:    deepAHTMLHeader.Name,
+					size:    int64(deepAHTMLHeader.UncompressedSize64),
+				},
+				"/aa/bb/c": {
+					data:    mustReadFile("../testdata/deep/aa/bb/c"),
+					isDir:   false,
+					modTime: deepCHTMLHeader.ModTime(),
+					mode:    deepCHTMLHeader.Mode(),
+					name:    deepCHTMLHeader.Name,
+					size:    int64(deepCHTMLHeader.UncompressedSize64),
+				},
+				"/": {
+					isDir: true,
+					mode:  os.ModeDir | 0755,
+					name:  "/",
+				},
+				"/aa": {
+					isDir: true,
+					mode:  os.ModeDir | 0755,
+					name:  "/aa",
+				},
+				"/aa/bb": {
+					isDir: true,
+					mode:  os.ModeDir | 0755,
+					name:  "/aa/bb",
+				},
+			},
+		},
 	}
 	for _, tc := range tests {
 		t.Run(tc.description, func(t *testing.T) {
@@ -155,7 +197,7 @@ func TestOpen(t *testing.T) {
 				if got, want := stat.Mode(), wantFile.mode; got != want {
 					t.Errorf("Mode(%v) = %v; want %v", name, got, want)
 				}
-				if got, want := stat.Name(), wantFile.name; got != want {
+				if got, want := stat.Name(), path.Base(wantFile.name); got != want {
 					t.Errorf("Name(%v) = %v; want %v", name, got, want)
 				}
 				if got, want := stat.Size(), wantFile.size; got != want {
@@ -166,6 +208,118 @@ func TestOpen(t *testing.T) {
 	}
 }
 
+func TestWalk(t *testing.T) {
+	Register(mustZipTree("../testdata/deep"))
+	fs, err := New()
+	if err != nil {
+		t.Errorf("New() = %v", err)
+		return
+	}
+	var files []string
+	err = Walk(fs, "/", func(path string, fi os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		files = append(files, path)
+		return nil
+	})
+	if err != nil {
+		t.Errorf("Walk(fs, /) = %v", err)
+		return
+	}
+	wantDirs := []string{
+		"/",
+		"/a",
+		"/aa",
+		"/aa/bb",
+		"/aa/bb/c",
+	}
+	sort.Strings(files)
+	if !reflect.DeepEqual(files, wantDirs) {
+		t.Errorf("got:    %v\nexpect: %v", files, wantDirs)
+	}
+}
+
+func TestHTTPFile_Readdir(t *testing.T) {
+	Register(mustZipTree("../testdata/readdir"))
+	fs, err := New()
+	if err != nil {
+		t.Errorf("New() = %v", err)
+		return
+	}
+	t.Run("Readdir(-1)", func(t *testing.T) {
+		dir, err := fs.Open("/")
+		if err != nil {
+			t.Errorf("fs.Open(/) = %v", err)
+			return
+		}
+		fis, err := dir.Readdir(-1)
+		if err != nil {
+			t.Errorf("dir.Readdir(-1) = %v", err)
+			return
+		}
+		if len(fis) != 3 {
+			t.Errorf("got: %d, expect: 3", len(fis))
+		}
+	})
+	t.Run("Readdir(>0)", func(t *testing.T) {
+		dir, err := fs.Open("/")
+		if err != nil {
+			t.Errorf("fs.Open(/) = %v", err)
+			return
+		}
+		fis, err := dir.Readdir(1)
+		if err != nil {
+			t.Errorf("dir.Readdir(1) = %v", err)
+			return
+		}
+		if len(fis) != 1 {
+			t.Errorf("got: %d, expect: 1", len(fis))
+		}
+		if fis[0].Name() != "aa" {
+			t.Errorf("got: %s, expect: aa", fis[0].Name())
+		}
+		fis, err = dir.Readdir(1)
+		if err != nil {
+			t.Errorf("dir.Readdir(1) = %v", err)
+			return
+		}
+		if len(fis) != 1 {
+			t.Errorf("got: %d, expect: 1", len(fis))
+		}
+		if fis[0].Name() != "bb" {
+			t.Errorf("got: %s, expect: bb", fis[0].Name())
+		}
+		fis, err = dir.Readdir(-1) // take rest entries
+		if err != nil {
+			t.Errorf("dir.Readdir(1) = %v", err)
+			return
+		}
+		if len(fis) != 1 {
+			t.Errorf("got: %d, expect: 1", len(fis))
+		}
+		if fis[0].Name() != "cc" {
+			t.Errorf("got: %s, expect: cc", fis[0].Name())
+		}
+		fis, err = dir.Readdir(-1)
+		if err != nil {
+			t.Errorf("dir.Readdir(1) = %v", err)
+			return
+		}
+		if len(fis) != 0 {
+			t.Errorf("got: %d, expect: 0", len(fis))
+		}
+		fis, err = dir.Readdir(1)
+		if err != io.EOF {
+			t.Errorf("error should be io.EOF, but: %s", err)
+			return
+		}
+		if len(fis) != 0 {
+			t.Errorf("got: %d, expect: 0", len(fis))
+		}
+	})
+}
+
 // Test that calling Open by many goroutines concurrently continues
 // to return the expected result.
 func TestOpen_Parallel(t *testing.T) {
diff --git a/testdata/deep/a b/testdata/deep/a
new file mode 100644
index 00000000..e69de29b
diff --git a/testdata/deep/aa/bb/c b/testdata/deep/aa/bb/c
new file mode 100644
index 00000000..e69de29b
diff --git a/testdata/readdir/aa b/testdata/readdir/aa
new file mode 100644
index 00000000..e69de29b
diff --git a/testdata/readdir/bb b/testdata/readdir/bb
new file mode 100644
index 00000000..e69de29b
diff --git a/testdata/readdir/cc b/testdata/readdir/cc
new file mode 100644
index 00000000..e69de29b