To improve reliability as a device, and perform brake force control by a driver.

This device comprises a service brake system applying brake force in accordance with actuating of a brake pedal 10 for a service brake to act in each wheel, parking brake provided in at least front/rear any two wheels, parking brake link 50 connected mechanically to this parking brake by a wire 42, electromagnetic driven engaging means 52, 54, 56 provided in the parking brake link 50 to be capable of integrally engaging the parking brake link 50 and the brake pedal 10 for the service brake, engagement control means placing the electromagnetic driven engaging means 52, 54, 56 in a release condition when the service brake system is normal and in an engaged condition when the service brake system is abnormal, and a parking brake manually operating member 40 having an engaging protrusion 48 engaged in a parking brake acting direction relating to the parking brake link 50.