The present invention provides a vertical MOSFET which has striped trench gate structure which can secure avalanche resistance without increasing Ron. A vertical MOSFET 100 comprises a plurality of gate trenches 7 which is arranged in stripes, an array which is sandwiched with the plurality of gate trenches 7 and includes N+ source regions 4N+ and P+ base contact regions 5P+, and a diode region (anode region 6P+) which is formed so as to contact with two gate trenches 7. The N+ source regions 4N+ and the base contact regions 5P+ are alternately arranged along a longitudinal direction of the gate trench 7. Size of the diode region (anode region 6P+) corresponds to at least one of the N+ source regions 4N+ and two of the P+ base contact regions 5P+.