A farming device for benthic organisms, which is submerged in a water tank or a body of water, is constituted of a plurality of tray-form containers, which are the cultivating floor for benthic organisms such as bivalves, and are stacked in the vertical direction, with a central cavity passing through the stacked cultivating floors in the vertical direction and horizontal gaps defined between the cultivating floors, the cultivating floors communicating with the cavity.