ExcelVBAでutf-8指定でファイル読み込みする

ADO(ActiveX Data Objects) 使う

Sub Sample1()
    Dim buf As String, Target As String
    Target = "D:\Work\UTF-8のテキスト.txt"
    With CreateObject("ADODB.Stream")
        .Charset = "UTF-8"
        .Open
        .LoadFromFile Target
        buf = .ReadText
        .Close
        MsgBox buf
    End With
End Sub