PURPOSE: To combine a hydraulic continuous brake device arranged in the secondary side of a transmission with a lock brake, in the drive unit of a power vehicle.

CONSTITUTION: On the drive device of power vehicle having a transmission with at least driven shaft and continuous brake device, the continuous brake device 16 provided with a mechanical brake device 24 having a lock function (parking function) is arranged on the shafts 12, 40 common to both brake devices 16, 24. Meantime, the driven shaft 12 and the shaft 40 provided by displacing to the driven shaft are considered as a common shaft. The continuous brake device 16 and the brake device 24 having the lock function can be driven together or individually by a high angular velovity against the driven shaft 12 by a rapid transmission.