Maruto Bicycle Co., Ltd., 1955 ?
Mike was kind enough to send me this scan of a Maruto advertisement, and then shortly afterwards I found an ad for a copy of the owner's manual on the Yahoo.jp sell site (similar to eBay, but focused on Japanese items). The company Maruto Bicycle principally made bicycles, but also sold two models of machines which I'm assuming were both mopeds. Per the Japanese Wikipedia entry, one was called the Maruto, or possibly Mart (マルト号) and the other was called the Auto Merry (オートメリー号). No other data is available.