A stacked cooler includes a plurality of refrigerant flow passages and a plurality of semiconductor modules. The refrigerant flow passages and the semiconductor modules are stacked alternately, and each of opposite surfaces in a stacking direction of each of the semiconductor modules is in contact with a corresponding one of the refrigerant flow passages, thereby cooling the semiconductor modules. The semiconductor modules generate different amounts of heat. One or a plurality of the semiconductor modules and one or a plurality of the semiconductor modules are arranged in each of arrangement spaces adjacent to the refrigerant flow passages so that a difference in amount of heat generated between the respective arrangement spaces becomes small. Consequently, cooling capability is equalized throughout the respective arrangement spaces, enabling reduction in waste due to excessive cooling.