A controller for a system includes a first control section and a second control section. The system includes an electrical actuator, a switch switching the electrical actuator between a power supply state and a power cutoff state, and a drive section driving the switch. The drive section outputs, to the switch, a drive signal to drive the switch based on a command signal for switching of the switch. The first control section determines a switch state based on the command signal, and the second control section determines a switch state based on the drive signal. At least one of the first control section and the second control section determines the electrical actuator to be in the power supply state on the condition that the first control section determines the switch to be in the power supply state, and the second control section also determines the switch to be in the power supply state.