Fumon-in, Buddhist temple in Kameido, Japan

Fumon-in is a Shingi-Shingon temple of the Chizan school in Kameido, Tokyo, whose mountain name is Fukuju-san. It enshrines Bishamonten as one of the seven deities of the Kameido Shichifukujin pilgrimage. Its main image was changed from Sho-Kannon to Dainichi Nyorai between 1772 and 1781 by the monk Eihan.

Founded in 1522 as Fumon-in of Zenno-ji on the grounds of a castle in Miyahara, Toshima district, Musashi Province, belonging to Chiba Jitane, its first main image was a Sho Kannon. Chiba had the temple built after his retainer Sada Zenjimori Mitsumoto, condemned to death on a false charge, was saved through faith in that Kannon. A separate hall was later added, and in 1622 the temple moved to its present site in Kameido.

Fumon-in is one of the seven deities of the Kameido Shichifukuso pilgrimage, where it houses Bishamonten. The main image was changed from Sho-Kannon to Dainichi Nyorai by the monk Eihan during the An'ei era (1772–1781). In the Edo period the temple was a branch of Hoyu-in at Yakuo-zan Shintei-ji in Aoto, Katsushika.

Fumon-in stands about 11 minutes on foot from the north exit of Kameido Station. The temple is one of the seven stops on the Kameido Shichifukujin circuit, where it honours Bishamonten, so visitors walking the route will find it alongside the other six sites.

The temple bell, being transported by boat when the temple moved to this site in 1622, fell into the Sumida River and could not be recovered; this accident is said to be the origin of the place name Kamegafuchi ("Bell Hollow").