A semiconductor device including a semiconductor substrate, first and second transistor sections and a diode section provided on the substrate, is provided. The diode section is arranged to be adjacent to and sandwiched between the first and second transistor sections in a predetermined arrangement direction. The diode section includes a drift region; a base region above the drift region; first cathode regions and second cathode regions below the drift region. The first and second transistor sections each include a collector region. The first cathode regions are provided continuously between the collector regions of the first and second transistor sections. One end and another end of the first cathode regions in the arrangement direction are in contact with the collector regions of the first and second transistor sections, respectively. The first and second cathode regions are in contact with each other and alternating in a direction orthogonal to the arrangement direction.