To prevent abrasion and seizure of contact parts of a swash plate and a shaft as well as to improve controllability by smoothing the axial motion (the tilting motion) of the swash plate.

A link mechanism 41 for tiltably connecting a swash plate 10 to a thrust flange 40 and transmitting torque of the thrust flange 40 to the swash plat 10 is constituted of a bracket 10e provided on the front side end surface 10c of the swash plate 10, a pair of guide grooves 10f, 10g provided in parallel on the bracket 10e, a rod 43 screwed to the swash plate side end surface 40a of the thrust flange 40, and a pair of spherical parts 43a, 43b provided on the tip of the rod 43. Since a pair of spherical parts 43a, 43b of the link mechanism 41 are relatively slidably fitted to a pair of guide grooves 10f, 10g provided across the top dead center (t) of the swash plate 10, the rotation around the Y-axis of the swash plate 10 can be prevented.