PROBLEM TO BE SOLVED: To perform simultaneous drive of two radial piston pumps in a double row and to solve such a problem that when an auxiliary pump is driven, it is difficult to ensure a suction passage area sufficient to two pumps in a double row in terms of structure. SOLUTION: In a double row radial piston pump in tandem arrangement, since a suction passage for two sets of pumps in front and rear rows and two sets of discharge flow passages are situated at a pintle switch valve stem situated at a central part, it is necessary that a port is formed in a large diameter to reduce the occurrence of fluid resistance of a suction port. Thereby, the suction passage is formed in an eccentric circle including the central line of a pintle switch valve stem and simultaneously, an auxiliary pump drive shaft situated at the rear part of the pump is liquid-tightly and slidably extended through the end part of the pintle switch valve stem and by the passage of it through the suction passage, a necessary port area is ensured.
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