According to one embodiment, a semiconductor device includes an emitter electrode (51), a collector electrode (52), an emitter-side trench gate electrode (53) and a collector-side trench gate electrode (54). It furthermore includes a semiconductor member, and first and second insulating members. The semiconductor member is located between the emitter and collector electrodes, and includes a first (n-type) semiconductor drift region (11), a second (p-type) semiconductor region (12) between the first semiconductor region and the first electrode, a third (n-type) semiconductor region (13) between the second semiconductor region and the first electrode, a fourth (p-type) semiconductor region (14) between the second semiconductor region and the first electrode, a fifth (p-type) semiconductor region (15) between the first semiconductor region and the second electrode, a sixth (n-type) semiconductor region (16) between the fifth semiconductor region and the second electrode, and a seventh (p-type) semiconductor region (17) between the fifth semiconductor region and the second electrode. The p-type body contact regions at the emitter (14) and at the collector side (17) may be different by a factor of 20 as far as their doping levels or their volumes are concerned.