A semiconductor device that comprises: a plurality of IGBT elements; and freewheeling diodes that respectively correspond to the IGBT elements. The IGBT elements are connected in parallel and driven. Each of the IGBT elements has: a collector region (11); a drift region (10); a body region (13); trench gates (G1, G2, G3, G4) that pass through the body region and arrive at the drift region; and an emitter region that (14) that is surrounded by the body region and contacts the trench gates via an insulating film. Each of the IGBT elements also has: active cells at which the emitter region is formed; dummy cells at which the emitter region is not formed; and active dummy cells at which the emitter region is not formed. The active dummy cells include float cells at which the body region is electrically floating. The number of float cells is 5%-35% of the total number of active cells and active dummy cells.