A power source switching device includes a first switch circuit provided between a first power source and a load section, a second switch circuit provided between a second power source and the load section, a third switch circuit provided between the first power source and the load section in series with the first switch circuit, a fourth switch circuit provided between the second power source and the load section in series with the second switch circuit, a logic circuit that controls the third and the fourth switch circuits to prevent at least one of the third and fourth switch circuits from turning on while both of the first and second switch circuits are in an on state, and a control circuit that controls the first switch circuit, the second switch circuit, and the logic circuit.