To provide a swash plate type variable displacement piston pump having simple construction for easily reducing pulsation.

The swash plate type variable displacement piston pump 40 comprises a pulsation reducing device 41 mounted on an outside face 12a of a case 12 with a screw ember, the pulsation reducing device 41 having a pilot hole 42 formed in the case 12 in the direction of the axial center in communication with a valve plate 19 and a throttle hole 44 formed in the outside face 12a in communication with the pilot hole 42. A cylinder member 47 in a cylindrical shape is fixed to the outside face 12a of the case 12 with a screw member 46. A bolt member 50 is fitted through the cylinder member 47, and a shaft portion 48a of the bolt member 50 is threaded to the outside wall of the cylinder member 47 so as to be moved into the cylinder member 47 in the direction of the axial center with a nut 49. A reflecting plate 43 is fitted through a cylinder chamber 53 and a spring member 51 is provided between the reflecting plate 43 and a moving member 48 of the bolt member 50.