To prevent operating liquid from flowing to the periphery of a driving shaft, so as to improve lubricating performance around a driving shaft supporting part without increasing manufacturing costs, deteriorating durability of components, and enlarging a device, by a structure having the small number of parts and by which large stress is prevented from acting the components.

An eccentric cam 15 is integrally provided on a driving shaft 11, and a plurality of plungers 18 are radially provided on a housing 6. An auxiliary ring 39 is relatively rotatably provided on the outer periphery of the eccentric cam 15, and respective plungers 18 are pressed through the auxiliary ring 39. Bellows 41a, 41b for surrounding the driving shaft 11 and for partitioning the housing 6 into an operating liquid chamber 44 and a lubricating liquid chamber 45 are arranged between the auxiliary ring 39 and the housing 6.