To provide a power supply apparatus that can boost input voltage from a low-power input source. A power supply apparatus is provided, including: an inductor connected to an input terminal to which input voltage is applied; a first switch connected between a point between the inductor and an output terminal, and a ground terminal; a drive unit operating the first switch using a signal having amplitude corresponding to the input voltage; and a control unit controlling operation of the first switch and/or outputting of output voltage from the output terminal, according to the output voltage output at the output terminal, wherein the control unit has a first hysteresis comparator, for controlling operation of the first switch, detecting the output voltage output at the output terminal, and/or a second hysteresis comparator, for controlling outputting of the output voltage, detecting the output voltage output at the output terminal.