A semiconductor device including a semiconductor substrate is provided. The semiconductor substrate includes a transistor region, and the transistor region includes a drift region, a plurality of trench portions, a plurality of emitter regions and a plurality of contact regions, and an accumulation region provided between the drift region and the plurality of emitter regions in a depth direction, and having a higher first-conductivity-type doping concentration than the drift region. A first outermost contact region is an outermost one of the plurality of contact regions in a direction parallel to the first direction, and a length of the first outermost contact region in the first direction is longer than a length in the first direction of one contact region of the plurality of contact regions other than the first outermost contact region, and the accumulation region terminates at a position below the first outermost contact region.