A Japanese man runs it and carries a very good selection of bikes (Bianchi, Trek, etc.) and bike accessories.
In Amakubo near the Coco's-El Torito intersection called El Delaporte. The shop is small and on a side street to the right off of Higashi Odori, if you're coming from the north. The 24-hour convenience store with a smiling sunshine face is at the end of the street on which De Laporte is located.