PURPOSE: To equalize the load added onto connecting rods, by attaching the plural connecting rods to a swash plate by a ring holding plate, and forming this holding plate with holding parts to hold balls.

CONSTITUTION: The motion of a swash plate 111 in a cylinder housing 115, is transmitted to a piston 119 through a connecting rod 131, and this piston 119 is reciprocated in a cylinder 117. The connecting rod 131 is formed with a ball 133 and a holding ball 139, and held by a holding plate 137. Thus, the holding plate 137 can press the holding ball 139 always with the preset pressure, and consequently, the value of the load of the holding plate 137, added onto the connecting rod 131, can be defined.