The pulse width modulation control method and RF band power supply device according to the present invention are a pulse width modulation (PWM) control of a single phase PWM inverter in which the modulated wave frequency fs of a modulated wave is set in the RF band. The present control includes each of (a) a frequency synchronization control in which the carrier wave frequency fc of the carrier wave is set to even N times the modulated wave frequency fs, (b) an odd function control in which the modulated wave is set to a sine wave of an odd function and the carrier wave is set to a triangle wave of an odd function, and (c) a phase synchronization control in which the carrier wave is synchronized in phase with the modulated wave in each cycle of the modulated wave.