Rearing experiments were carried out to study relationships between feeding materials, feeding methods and increase of soft parts of Corbicula japonica. Artifi cial soy food was very effective for the increase of soft parts. Diatom Thalassiosira pseudonana, one main food of the clams in Lake Shinji, increased the soft part, but the effi ciency was not so high. Two feeding methods, “feeding once a day” and “feeding little by little for 12 hours a day” showed almost the same growth of soft parts under the condition of circular running water.