In an edge termination region, a second gate runner for a current sensor is formed between a first gate runner for a main semiconductor device and an active region. The second gate runner surrounds the periphery of the active region in a substantially rectangular shape having an opening. One end of the second gate runner is connected to all of the gate electrodes of the current sensor, and the other end is connected to the first gate runner at between a gate pad and an OC pad. This makes it possible to increase the gate capacitance of the current sensor as the current sensor switches ON and OFF when a pulse-shaped gate voltage is applied to the gate pad by an amount proportional to the surface area of the second gate runner.