A semiconductor device is disclosed having a plurality of gate trenches formed on the surface thereof, each filled with a gate insulating film and a gate electrode. A transistor region is defined between adjacent gate trenches forming a pair, and includes an n+-type emitter region, a p-type base region, and an n−-type drift region disposed lateral to each gate trench in the pair, in order in a depth direction of the gate trench from a front surface side of the semiconductor layer. A p+-type collector region disposed on a back surface side of the semiconductor layer with respect to the n−-type drift region. A plurality of emitter trenches are formed one either side of each of the gate trenches in the pair of gate trenches.