In the direction from the first main surface toward the second main surface through each of the second impurity region and the fourth impurity region, a concentration profile of an n-type impurity has a second relative maximum value and a fourth relative maximum value located closer to the first main surface than a position where the second relative maximum value is exhibited. The fourth relative maximum value is larger than the third relative maximum value, the third relative maximum value is larger than the second relative maximum value, and the second relative maximum value is larger than the first relative maximum value.