A gate driver that drives a field-effect transistor on the basis of an input signal includes a comparator that compares an applied voltage applied between the drain and the source of a field-effect transistor to a reference voltage for detecting noise occurring between the drain and the source of the field-effect transistor, and a gate voltage switching circuit that, if the field-effect transistor is off, switches the voltage applied between the gate and the source of the field-effect transistor from a first voltage to a second voltage when the output of the comparator transitions from a state indicating that the applied voltage between the drain and the source is less than the reference voltage to a state indicating that the applied voltage between the drain and the source is equal to or greater than the reference voltage.