PURPOSE: To enable to confirm that the parking brake is in action by a method wherein the indication of the state of action of parking brake is shown only when the actual braking force of an applied parking brake exceeds the set value.

CONSTITUTION: An inclination sensor 2 measures the inclination of a vehicle in the running direction. A reference braking force setting part 4 sets the reference braking force of a parking brake in accordance with a signal by being inputted a signal outputted by the inclination sensor 2. A braking force sensor 6 detects the braking force of the parking brake. A controlling part 8 compares both signals, which are sent from the reference braking force setting part 4 and the braking force sensor 6 to be inputted thereto, with each other and outputs a signal to drive an indicator 10 in response to the result of comparison. The indicator 10 shows the indication in response to a signal by being inputted as output signal sent from the controlling part 8.