FileSystemObject を使いましょう。 参照設定で "Microsoft Scripting Runtime" を参照した場合は Dim textValue As String Dim fso As Scripting.FileSystemObject Dim ts As Scripting.TextStream Set fso = New Scripting.FileSystemObject Set ts = fso.OpenTextFile("D:\test.txt", ForReading) textValue = ts.ReadAll ts.Close Me.TextBox1.Text = textValue 参照設定をしない場合は Const ForReading = 1 Dim textValue As String Dim fso As Object Dim ts As Object Set fso = CreateObject("Scripting.FileSystemObject") Set ts = fso.OpenTextFile("D:\test.txt", ForReading) textValue = ts.ReadAll ts.Close Me.TextBox2.Text = textValue です。