Provided is a semiconductor device comprising: a semiconductor substrate; a plurality of peaks of a doping concentration provided on a back surface of the semiconductor substrate; and a flat part, with a doping concentration more than or equal to 2.5 times a substrate concentration of the semiconductor substrate, provided between the plurality of peaks in a depth direction of the semiconductor substrate, wherein at least one of the plurality of peaks is a first peak provided on a front surface side relative to the flat part, wherein a doping concentration of the first peak is less than or equal to twice the doping concentration of the flat part.