A regulator device includes: a plurality of regulators that are equipped in parallel between a power input terminal and a power output terminal and converts a power inputted from the power input terminal to output to the power output terminal; a dummy load circuit that is coupled to a power output system different from a power output system to the respective power output terminal of the plurality of regulators; a selector that selects a regulator to carry out an output to the power output terminal and a regulator to carry out an output to the dummy load circuit among the plurality of regulators; and a controller that obtains conversion efficiency characteristic information representing a characteristic of power conversion efficiency relative to a current flowing in the dummy load circuit for the regulator to carry out an output to the dummy load circuit.