A power supply device includes a power supply, a conversion unit performing voltage conversion on electric power to be supplied from the power supply, and a control unit generating a first control signal for inputting or outputting a target voltage or a target current to and from the conversion unit by a feedback loop, and controlling the conversion unit based on the first control signal and a second control signal for detecting a state of the power supply, generated outside the feedback loop. The control unit sets a specific parameter of the second control signal based on a feedforward term based on the output of the power supply and a feedback term in which the specific parameter included in at least one of electric power output from the power supply and input into the conversion unit and electric power output from the conversion unit, is a feedback component.