diff --git a/prompt/prompt.go b/prompt/prompt.go
index 0b9c3a2..3e985b6 100644
--- a/prompt/prompt.go
+++ b/prompt/prompt.go
@@ -17,6 +17,7 @@ type Prompt struct {
 	title     string
 	executor  Executor
 	completer Completer
+	chosen    int
 }
 
 func (p *Prompt) Run() {
@@ -41,14 +42,25 @@ func (p *Prompt) Run() {
 				res := p.executor(p.buf)
 				p.renderer.BreakLine(p.buf, res)
 				p.buf = NewBuffer()
+				p.chosen = -1
 			} else if ac.Key == ControlC || ac.Key == ControlD {
 				return
+			} else if ac.Key == BackTab || ac.Key == Up {
+				p.chosen -= 1
+			} else if ac.Key == Tab || ac.Key == ControlI || ac.Key == Down {
+				p.chosen += 1
 			} else {
 				InputHandler(ac, p.buf)
+				p.chosen = -1
 			}
 
 			completions := p.completer(p.buf)
-			p.renderer.Render(p.buf, completions)
+			if p.chosen >= len(completions) {
+				p.chosen = -1
+			} else if p.chosen < -1 {
+				p.chosen = len(completions) - 1
+			}
+			p.renderer.Render(p.buf, completions, p.chosen)
 		case w := <-winSizeCh:
 			p.renderer.UpdateWinSize(w)
 		case e := <-exitCh:
@@ -130,5 +142,6 @@ func NewPrompt(executor Executor, completer Completer, maxCompletions uint8) *Pr
 		buf:       NewBuffer(),
 		executor:  executor,
 		completer: completer,
+		chosen: -1,
 	}
 }
diff --git a/prompt/render.go b/prompt/render.go
index 84518b3..9631f23 100644
--- a/prompt/render.go
+++ b/prompt/render.go
@@ -6,7 +6,6 @@ type Render struct {
 	out            *VT100Writer
 	row            uint16
 	col            uint16 // sigwinchで送られてくる列数を常に見ながら、prefixのlengthとbufferのcursor positionを比べて、completionの表示位置をずらす
-	chosen         uint8  // the index number of a chosen completion
 	maxCompletions uint8
 }
 
@@ -40,7 +39,7 @@ func (r *Render) UpdateWinSize(ws *WinSize) {
 	return
 }
 
-func (r *Render) RenderCompletion(words []string) {
+func (r *Render) RenderCompletion(words []string, chosen int) {
 	if len(words) == 0 {
 		return
 	}
@@ -51,7 +50,7 @@ func (r *Render) RenderCompletion(words []string) {
 	r.out.SetColor("white", "teal")
 	for i := 0; i < l; i++ {
 		r.out.CursorDown(1)
-		if i == int(r.chosen) {
+		if i == chosen {
 			r.out.SetColor("white", "turquoise")
 		} else {
 			r.out.SetColor("black", "cyan")
@@ -76,11 +75,11 @@ func (r *Render) Erase(buffer *Buffer) {
 	return
 }
 
-func (r *Render) Render(buffer *Buffer, completions []string) {
+func (r *Render) Render(buffer *Buffer, completions []string, chosen int) {
 	line := buffer.Document().CurrentLine()
 	r.out.WriteStr(line)
 	r.out.CursorBackward(len(line) - buffer.CursorPosition)
-	r.RenderCompletion(completions)
+	r.RenderCompletion(completions, chosen)
 	r.out.Flush()
 }