A semiconductor device has a semiconductor substrate including a first conductivity-type drift layer, a second conductivity-type base layer disposed in a surface layer portion of the drift layer, and a second conductivity-type collector layer and a first conductivity-type cathode layer disposed opposite to the base layer with respect to the drift layer. In the semiconductor substrate, an IGBT region and a diode region are alternately and repetitively arranged. The IGBT region and the diode region are divided by a boundary between the collector layer and the cathode layer. The collector layer is defined as a first collector layer. The semiconductor device includes a second collector layer having a second conductivity-type impurity concentration higher than that of the first collector layer, at a surface of the semiconductor substrate adjacent to the first collector layer and the cathode layer.