The present invention provides a voltage supplying device which supplies a voltage to a load capacitance to finish charging the load capacitance with a predetermined voltage within a predetermined charging period. The voltage supplying device includes a voltage supplying source, an impedance conversion circuit which performs impedance conversion for a voltage from the voltage supplying source and outputs the converted voltage, a first switching element connected between the impedance conversion circuit and the load capacitance, a bypass line for bypassing the impedance conversion circuit and the first switching element and supplying a voltage from the voltage supplying source to the load capacitance, and a second switching element provided on the bypass line. The impedance conversion circuit may include a voltage follower circuit for outputting the voltage supplied from the voltage supplying source by a first current drive capability, and a booster provided at an output stage of the voltage follower circuit, for outputting a current to be added to an output of the voltage follower circuit by a second current drive capability. The first switching element is turned on and the second switching element is turned off in a first period of the charging period and a second period subsequent to the first period, and the first switching element is turned off and the second switching element is turned on in a third period of the charging period subsequent to the second period. Furthermore, in the first period, both the voltage follower circuit and the booster are driven so that a voltage is outputted from the impedance conversion circuit by the first current drive capability and the second current drive capability. Also, in the second period, the voltage follower circuit is driven so that a voltage is outputted from the impedance conversion circuit by the first current drive capability.