First, second, fourth, and fifth impurity regions have a first conductivity type, and a third impurity region has a second conductivity type. The first to third impurity regions reach a first layer having the first conductivity type. The fourth and fifth impurity regions are provided on a second layer. First to fifth electrodes are provided on the first to fifth impurity regions, respectively. Electrical connection is established between the first and fifth electrodes, and between the third and fourth electrodes. A sixth electrode is provided on a gate insulating film covering a portion between the fourth and fifth impurity regions.