In particular, by obtaining a depth distribution of the n-type doping concentration of the n?-type drift layer 3, in the n?-type drift layer 3, the n-type doping concentration difference of the n?-type lifetime reduced layer 22 in which vanadium is doped and the first and the third n?-type layers 21, 23 in which vanadium is not doped may be obtained. Therefore, a value obtained by dividing the n-type doping concentration difference of the first and the third n?-type layers 21, 23 and the n?-type lifetime reduced layer 22 by four is substantially the vanadium concentration (≈[the n-type doping concentration difference of the first and the third n?-type layers 21, 23 and the n?-type lifetime reduced layer 22]/4) of the n?-type lifetime reduced layer 22.