A semiconductor device for restraining snapback is provided. The semiconductor device includes IGBT and diode regions. In a view of n-type impurity concentration distribution along a direction from a front surface to a rear surface, a local minimum value of an n-type impurity concentration is located at a border between cathode and buffer regions. A local maximum value of n-type impurity concentration is located in the buffer region. At least one of the buffer and cathode regions includes a crystal defect region having crystal defects in a higher concentration than a region therearound. A peak of a crystal defect concentration in a view of crystal defect concentration distribution along the direction from the front surface to the rear surface is located in a region on the rear surface side with respect to a specific position having the n-type impurity concentration which is a half of the local maximum value.