POWER-SUPPLY CONTROL DEVICE

A power-supply control device capable of reducing a size of a power-supply device including a main power-supply and a plurality of auxiliary power-supply systems and stably supplying electric power to the plurality of auxiliary power-supply systems is provided. The power-supply control device includes a DC/DC converter that steps down a power-supply voltage from a main battery and outputs the stepped-down power-supply voltage to a first auxiliary power-supply system and a second auxiliary power-supply system; and a controller that stops supply of electric power from the DC/DC converter to the second auxiliary power-supply system when a load of a heater is in a predetermined high-load state, and supplies electric power from the DC/DC converter to the second auxiliary power-supply system when the load of the heater changes from the predetermined high-load state to a predetermined low-load state.