This semiconductor device comprises: a plurality of power modules, each having a semiconductor element; a plurality of heat dissipation bases that are disposed via heat dissipation members on a heat dissipation surface side of the plurality of power modules, and that each have a heat dissipation fin; a frame having a plurality of openings; and a cover that covers the heat dissipation bases and the frame so as to form a refrigerant flow passage. The plurality of heat dissipation bases respectively block the plurality of openings. The cover has an elastic biasing part on a surface which contacts the heat dissipation fins. The heat dissipation bases are biased, by pressurization, toward the power modules.