A power supply control system having a first switch circuit configured to set a power supply line which connects a power supply unit and a power supply circuit to one of a connected state and a non-connected state, a first control unit configured to operate in one of a normal mode and a sleep mode in which a consumption current is smaller than in the normal mode, and to detect a magnitude of a current flowing into the first switch circuit and control an operation of the first switch circuit based on the detected magnitude of the current while operating in the normal mode, and a second control unit configured to control an operation of the first control unit based on the detection result of an opening-closing state detection unit configured to detect an opening-closing state of a battery lid provided to the power supply unit.