PURPOSE: To prevent plungers from turning over, by forming a surface, adapted with plungers to a lever member, in such a manner that a vertical component of tension of a spring applied to the plunger through the lever member is inverted in forward and return movement positions of the plunger.

CONSTITUTION: An adapting member 20 of a spring receiver 19, receiving a preload spring 18, is adapted to a spherically recessed place 56 in a lever member 21. A spherically recessed place 55 in a central part of the lever member 21 is adapted to a support point member 23 fixed to a cover 22. Further point end parts of plungers 26a, 26b in pressure regulating valves 70A, 70B are adapted to a pair of spherically recessed places 54a, 54b in the lower of the lever member 21. A surface adapted with the plunger to the lever member 21 is formed in such a manner that a direction y of a vertical component, with respect to the axial direction of the plunger, of a applied tension to the plunger through the lever member 21 by the preload spring 18 is inverted in a return movement position (full line position) and forward movement position (chain line position shifted by a distance L) of the plunger.