A semiconductor device is subjected to ON/OFF control by controlling a gate voltage according to a drive control signal (Ssw). In a turn-on operation for charging a gate in response to transition of drive control signal (Ssw) from a first level (0) to a second level (1), a drive signal (Sdr) is set to first level (0) to discharge the gate at a first time (t1) after end of a Miller period (200) of a gate voltage (Vg), thereby providing a voltage drop period (210) in which gate voltage (Vg) temporarily drops. At a second time (t2), drive signal (Sdr) is again set to second level (1) to start charging the gate.