As a part of ecomuseum planning scheme, biotope, called "Biotope Jiromaru", was newly constructed by the citizens of Ushirodani, Higashi-Hiroshima, on December 2, 2003. The aquatic biota were investigated in and around the biotope on February 19, July 7 and December 8, 2005. Forty-two species, which were mostly aquatic insects, were identified and listed. This is the first report of biota from this biotope.