A second impurity region is surrounded by a first impurity region at a first main surface. A third impurity region of the first main surface sandwiches the second impurity region with the first impurity region. Fourth and fifth impurity regions of a second main surface sandwich the first impurity region with the second impurity region. A control electrode layer is opposite to the second impurity region with an insulating film interposed. That portion of the second main surface which is opposite to the portion of the first main surface where the first impurity region is formed surrounds the regions for forming the fourth and fifth impurity regions of the second main surface, and it is a region of the first conductivity type or a region of the second conductivity type having impurity concentration not higher than that of the first impurity region.