PURPOSE: To secure responsiveness to a panic brake even during the operation of a regenerative device and make the changeover to a service brake from a regenerative brake smooth by controlling control pressure be applied to a pressure reducing valve according to the depression quantity of a brake pedal.

CONSTITUTION: During the operation of a regenerative device 30, a valve 76 for supplying control pressure is closed, and pressure supplied to a service brake 78 from a pressure reducing valve 77 is reduced so as to perform braking with the recovery of kinetic energy as the main by the regenerative device 30. On the other hand, the depression quantity of a brake pedal 1 is detected by a detecting means 73, and this detection value is compared with the preset depression quantity by a comparing means 71. When the detection value becomes the set value or more, the valve 76 is opened by a driving means 75, and control pressure is applied to the pressure reducing valve 77, so that the pressure reducing valve 77 drives the service brake 78 by the output of a brake valve 2 corresponding to the control pressure to perform sudden braking. Responsiveness at the sudden braking time can be therefore secured even during the operation of the regenerative device 30.