A semiconductor device according to the present invention includes a semiconductor substrate, having an emitter layer of a first conductivity type, a collector layer of a second conductivity type and a drift layer of the first conductivity type sandwiched therebetween, the emitter layer disposed at a front surface side of the semiconductor substrate and the collector layer disposed at a rear surface side of the semiconductor substrate, a base layer of the second conductivity type between the drift layer and the emitter layer, a buffer layer of the first conductivity type between the collector layer and the drift layer, the buffer layer having an impurity concentration higher than that of the drift layer, and having an impurity concentration profile with two peaks in regard to a depth direction from the rear surface of the semiconductor substrate, and a defect layer, formed in the drift layer and having an impurity concentration profile with a half-value width of not more than 2 μm in regard to the depth direction from the rear surface of the semiconductor substrate.