PURPOSE: To make small the outside dimensions and facilitate design of the shaft and its surroundings by constructing at least one of the bearings to bear the shaft in the form as static pressure bearing and by equipping this or these static pressure bearings with a working liquid supply mechanism in communication with the liquid's high pressure side.

CONSTITUTION: If as the rear bearing 12 for shaft 1 is a static pressure bearing, which utilizes the self high-pressure working liquid of a pump or motor, is used, the bearing 12 is put in communication wuth the-high-pressure working liquid passage 15 through pipes 16, 17, and is composed of a throat 18, a pocket 19 and a land 20. Because the self high-pressure liquid pressure is used, any auxiliary pressure source is no more necessary and the static pressure bearing can be constructed with smaller outside dimensions than rolling bearings which have been used in conventional construction.