diff --git a/key_bind.go b/key_bind.go
index 42669e7f..0332e27d 100644
--- a/key_bind.go
+++ b/key_bind.go
@@ -16,13 +16,13 @@ type ASCIICodeBind struct {
 }
 
 // KeyBindMode to switch a key binding flexibly.
-type KeyBindMode string
+type KeyBindMode uint8
 
 const (
 	// CommonKeyBind is a mode without any keyboard shortcut
-	CommonKeyBind KeyBindMode = "common"
+	CommonKeyBind KeyBindMode = iota
 	// EmacsKeyBind is a mode to use emacs-like keyboard shortcut
-	EmacsKeyBind KeyBindMode = "emacs"
+	EmacsKeyBind
 )
 
 var commonKeyBindings = []KeyBind{
diff --git a/prompt.go b/prompt.go
index 31a76ea8..5d6d50c8 100644
--- a/prompt.go
+++ b/prompt.go
@@ -247,7 +247,8 @@ func (p *Prompt) handleKeyBinding(key Key) bool {
 		}
 	}
 
-	if p.keyBindMode == EmacsKeyBind {
+	switch p.keyBindMode {
+	case EmacsKeyBind:
 		for i := range emacsKeyBindings {
 			kb := emacsKeyBindings[i]
 			if kb.Key == key {