PURPOSE: To promote safety, by providing a device for warning of an unexpected start of a vehicle during the operation of a foot-depressed brake and by causing the device to generate a warning signal when it detects that the vehicle has started despite the operation of the foot-depressed brake after the detection of an electric power failure in the vehicle.

CONSTITUTION: When a foot-depressed brake is pressed down, a switch 3a is turned on and a braking signal BK is generated by a braking detector 3 and applied to the AND gate 702 of a warning circuit 700 through the braking signal shaping circuit 600 of a warning device 1. The AND gate 702 is opened when it has received both the high-level version of a vehicle speed shaping signal 100a from a vehicle speed shaping circuit 100 connected to a vehicle speed sensor 500 and that of a vehicle stop signal 500a from a vehicle stop detection circuit 500. When a signal 705a is generated by a counter 705 in response to a vehicle speed reset signal 200a from a set vehicle speed detection circuit 200 and a signal 702a is sent out from the AND gate 702, another AND gate 303 is opened to cause a piezoelectric buzzer 701 to buzz.