A power conversion device configured to be disposed between an AC power source and a load, comprising: a rectifier circuit unit that is configured to rectify a voltage of the AC power source; a smoothing unit that is configured to smooth a DC voltage on the load side of the rectifier circuit unit; a short-circuiting unit that is disposed on the AC power source side of the smoothing unit and that is configured to short-circuit the AC power source; a step-up reactor that is disposed on the AC power source side of the short-circuiting unit that includes a switching element; at least one of a reactor current detecting unit that is configured to detect the current of the step-up reactor and a bus voltage detecting unit that is configured to detect an output voltage of the smoothing unit; a counterflow preventing element that is configured to prevent a counterflow of the current from the smoothing unit to the AC power source; a switching control unit that is configured to generate a plurality of drive pulses by making the output signal of the reactor current detecting unit or the bus voltage detecting unit as an input and that outputs a control signal for turning on or off the short-circuiting unit using the plurality of drive pulses, the plurality of drive pulses each having phases in which ON and OFF are inverted; a switching frequency changing unit that is disposed between the switching control unit and the short-circuiting unit and that is configured to be capable of changing a frequency of the control signal by using the plurality of drive pulses, characterized in that the switching frequency changing unit includes logic circuits such as an OR circuit or an AND circuit, and the switching control unit includes: a bus voltage control unit; a reactor current control unit; and a drive pulse generating unit that is configured to generate the plurality of drive pulses for operating the switching element based on an ON-duty computed by the reactor current control unit or the bus voltage control unit, wherein two or more control signals (S1, S2) output from the switching control unit are input to the switching frequency changing unit, and wherein by properly combining the logic circuits the frequency of an output signal of the switching frequency changing unit is higher than the frequency of an input signal. a rectifier circuit unit that is configured to rectify a voltage of the AC power source; a smoothing unit that is configured to smooth a DC voltage on the load side of the rectifier circuit unit; a short-circuiting unit that is disposed on the AC power source side of the smoothing unit and that is configured to short-circuit the AC power source; a step-up reactor that is disposed on the AC power source side of the short-circuiting unit that includes a switching element; at least one of a reactor current detecting unit that is configured to detect the current of the step-up reactor and a bus voltage detecting unit that is configured to detect an output voltage of the smoothing unit; a counterflow preventing element that is configured to prevent a counterflow of the current from the smoothing unit to the AC power source; a switching control unit that is configured to generate a plurality of drive pulses by making the output signal of the reactor current detecting unit or the bus voltage detecting unit as an input and that outputs a control signal for turning on or off the short-circuiting unit using the plurality of drive pulses, the plurality of drive pulses each having phases in which ON and OFF are inverted; a switching frequency changing unit that is disposed between the switching control unit and the short-circuiting unit and that is configured to be capable of changing a frequency of the control signal by using the plurality of drive pulses, characterized in that the switching frequency changing unit includes logic circuits such as an OR circuit or an AND circuit, and the switching control unit includes: a bus voltage control unit; a reactor current control unit; and a drive pulse generating unit that is configured to generate the plurality of drive pulses for operating the switching element based on an ON-duty computed by the reactor current control unit or the bus voltage control unit, wherein a bus voltage control unit; a reactor current control unit; and a drive pulse generating unit that is configured to generate the plurality of drive pulses for operating the switching element based on an ON-duty computed by the reactor current control unit or the bus voltage control unit, wherein two or more control signals (S1, S2) output from the switching control unit are input to the switching frequency changing unit, and wherein by properly combining the logic circuits the frequency of an output signal of the switching frequency changing unit is higher than the frequency of an input signal.