Provided is a power converter capable of reliably turning OFF a switching element before turn-OFF of a diode even with a fluctuation in rpm so as not to generate a backflow of a current. The power converter includes a diode ON-interval monitoring unit (18) configured to measure a change rate of a diode ON detection interval signal. When a diode ON detection interval change rate signal (S20) exhibits a decrease on a negative side and is smaller than a predetermined value (an absolute value thereof exceeds a predetermined value), an OFF-timing of the switching element is advanced by a predetermined value or larger, to thereby reliably turn OFF the switching element before the turn-OFF of the diode even with the fluctuation in rpm.