Const adTypeText = 2
Const adSaveCreateOverWrite = 2

Set Src = CreateObject("ADODB.Stream")
Src.Open
Src.Type = adTypeText
Src.Charset = "ISO-2022-JP"
Src.LoadFromFile "L:\SJIS.txt"

Set Dst = CreateObject("ADODB.Stream")
Dst.Open
Dst.Type = adTypeText
Dst.Charset = "ISO-2022-JP"
Src.CopyTo Dst
Src.Close

Dst.SaveToFile "L:\JIS.txt", adSaveCreateOverWrite
Dst.Close

Set Src = Nothing
Set Dst = Nothing