I believe it was an Aerospatiale AS 360, as that is what Ogawa Air Inc. operates. That is only inference though.
Last night's NHK news gave the type, which I recognised as European, but I was semi comatose from a half hour report on the G8 summit, and not paying attention.
Edit.
施設紹介|ヘリコプター遊覧飛行の小川航空