PURPOSE: To easily release ice by buoyancy by providing means for enhancing the releasability of ice at a lower end, the periphery or the outer surface of an aluminum plate in an icemaking plate arranged in an ice reservoir and having a refrigerant circuit on the aluminum plate.

CONSTITUTION: A part having no refrigerant circuit 7 is formed over a length L at a lower end of an aluminum plate 30, and further a region 19 having a thickness loss than the thickness T of a part except it in thickness (t) is formed over a length 1 of the lower end. In order to release ices 9 adhering to both surfaces of an icemaking plate, hot water is supplied to the circuit 7, and then ice 9 of a part in contact with the plate 30 is melted. The circuit 7 is not provided at the end of the plate 30, and its thickness (t) is reduced, and hence ice 9 is not so grown on the end of the plate 30. Accordingly, the ice 9 of the end is released earliest, and then the entire ice 9 is operated by buoyancy, and hence preferably released.