A power source control circuit includes a USB power supply portion that supplies electric power from a power source circuit to a secondary battery, a solar power supply portion, and a monitoring circuit. A monitoring circuit causes a solar power supply portion to stop the supply of the electric power to the secondary battery if the electric power is supplied from the power source circuit. In this way, if both the power supply by the power source circuit and the power supply by power generation by the solar cell can be performed, the power source control circuit can charge the secondary battery from the power source circuit which is a stable power source, and thus, it is possible to easily secure the electric power for driving the system.