To prevent an arc discharge and an electrical shock from occurring when a connector connection part is handled.

This power cutout system for vehicle comprises a power cutout means 13 having a power cutout part 15 installed in a vehicle electric circuit 1 on the power supply upstream side of the connector connection part 4 installed in the vehicle electric circuit 1 and capable of bringing the vehicle electric circuit 1 into a nonconductive state and a control part 14 capable of controlling the power cutout part 15 and a lock detection means 12 as a cutout signal input means for inputting power cutout signals into the control part 14 when the connector connection part 4 is connected or disconnected. When the lock detection means detects an unlocking, the vehicle electric circuit 1 is brought into the nonconductive state on the power supply upstream side of the connector connection part 4.