A gate pad electrode and a source electrode are disposed, separately from one another, on the front surface of a super junction semiconductor substrate. A MOS gate structure formed of n source regions, p channel regions, p contact regions, a gate oxide film, and polysilicon gate electrodes is formed immediately below the source electrode. The p well regions are formed immediately below the gate pad electrode. The p channel regions are linked to the p well regions via extension portions. By making the width of the p well regions wider than the width of the p channel regions, it is possible to reduce a voltage drop caused by a reverse recovery current generated in a reverse recovery process of a body diode. Breakdown of a portion of a gate insulating film immediately below the center of the gate pad electrode and breakdown of the semiconductor device are thus prevented