PURPOSE: To achieve miniaturization and reduction of weight of an additional device including a brake, by providing a plunger pump for hydrostatically rotating a converter, a means for converting energy of high-pressure oil to be generated by the plunger pump into heat, and a cooler for cooling high-temperature oil.

CONSTITUTION: A pump shaft 1 connected to piston cylinders 2 for brake pumps (plunger pumps) is driven by a connecting part of a vehicle, pistons 3 in the cylinders 2 are reciprocated by the rotation of a turning wheel 4 capable of being freely tilted, and oil sucked through a suction conduit 6 is discharged to a pressurizing conduit 7 after being pressurized. The pressurizing conduit 7 can be freely closed by a balance-type pressure valve 8 having a housing in which a cooling fin 51 is provided on its periphery, and an outlet side is connected to an inlet of an oil cooler 19 through a conduit 18. An outlet of the cooler 19 is connected to the suction conduit 6 through a low-temperature operated slide valve 15 with a thermo-plunger 16 by a conductor 20.