>>719,724
レスありがとうございます。
ソースはこんな感じです。

Module Module1

Public Declare Function GetPrivateProfileString Lib "kernel32" Alias "GetPrivateProfileStringA" (ByVal IpApplicationName As String,
ByVal IpKeyName As String, ByVal IpDefault As String, ByVal IpReturnedString As String, ByVal nSize As Integer, ByVal IpFileName As String) As Integer

End Module

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Dim intLength As Integer
Dim intReturnValue As Integer
Dim strReturnValue As String = Space(100)

intLength = GetPrivateProfileString("VALUES", "VALUE1", Nothing, strReturnValue, strReturnValue.Length, strFilePath)
TextBox1.Text = strReturnValue.Substring(0, intLength)

End Sub

※iniファイルの中身
[VALUES]
VALUE1=（あいうえお）
VALUE2=（かきくけこ）
VALUE3=（さしすせそ）