diff --git a/inputfield.go b/inputfield.go
index bf54254..261c736 100644
--- a/inputfield.go
+++ b/inputfield.go
@@ -1,6 +1,8 @@
 package messeji
 
 import (
+	"sync"
+
 	"github.com/hajimehoshi/ebiten/v2"
 	"github.com/hajimehoshi/ebiten/v2/inpututil"
 	"golang.org/x/image/font"
@@ -24,6 +26,8 @@ type InputField struct {
 
 	// readBuffer is where incoming runes are stored before being added to the input buffer.
 	readBuffer []rune
+
+	sync.Mutex
 }
 
 // NewInputField returns a new InputField. See type documentation for more info.
@@ -68,13 +72,13 @@ func (f *InputField) SetSelectedFunc(selectedFunc func() (accept bool)) {
 // Game.Update is called.
 func (f *InputField) Update() error {
 	f.Lock()
+	defer f.Unlock()
 
 	if !f.visible || rectIsZero(f.r) {
 		return nil
 	}
 
 	if !f.handleKeyboard {
-		f.Unlock()
 		return f.TextField.Update()
 	}
 
@@ -123,6 +127,5 @@ func (f *InputField) Update() error {
 		f.bufferModified()
 	}
 
-	f.Unlock()
 	return f.TextField.Update()
 }