Abstract: Control accuracy with regard to variation of output voltage is improved. A direct current converter unit (20) that steps up or steps down an input voltage (Vin) to be outputted, and a control unit (10) that controls output voltage (Vout) of the direct current converter unit (20) by a pulse width modulation signal (Sw) are provided; the direct current converter unit (20) is provided with a voltage detection circuit (24) that monitors the output voltage (Vout); the control unit (10) is provided with an A/D converter (13) that samples a monitored voltage value (Vd) of the voltage detection circuit (24); and a pulse oscillator (14) that controls the position of one edge by an A/D conversion synchronous signal (Ss) indicating the start of sampling by the A/D converter (13), and generates the pulse width modulation signal (Sw), which controls the position of the other edge based on the monitored voltage value (Vd).