An electric parking brake system that includes a parking brake, and an electric
motor, wherein the parking brake is activated by the electric motor. Operation
of the parking brake is controlled such that a vehicle is decelerated at a target
deceleration of a predetermined magnitude when an operation command to operate
the parking brake is issued by a driver via an operation switch while the vehicle
is running. If a service brake fails while a vehicle is running, when the driver
depresses the operation switch to issue the operation command to a parking brake
to brake the vehicle, the parking brake is controlled such that the vehicle is
decelerated at the target deceleration of the predetermined magnitude set on the
basis of the number of times of depressing the operation switch.
