PURPOSE: To prevent the occurrence of a crash of a bearing into an eccentric cam through constant press of the bearing against the eccentric cam by means of one plunger by setting a load exerted on the bearing by one plunger to a relatively constantly higher value than that by the other plunger.

CONSTITUTION: When an eccentric cam 1 is driven by means of a motor shaft 16, plungers 2 and 2a radially arranged to the eccentric cam 1 are reciprocated against springs 9a and 9a1, respectively, through a bearing 6 held to the outer periphery of the eccentric cam 1. In which case, the volumes of pump chambers 8 and 8a are increased or decreased and working fluid is fed with a pressure from suction valves 11 and 11a and through suction passages 12 and 12a to discharge valves 4 and 4A and discharge passages 13 and 13a. In thus formed plunger pump 10, a load exerted on the bearing 6 by a first plunger 2 is set to a value constantly higher than a load exerted on the bearing 6 by a second plunger 2a.