the journal 14 has a boss 15 having an outside circumferential surface formed with a threaded portion 16 the swash plate 17 has a threaded hole 18 the swash plate 17 is fixed to the journal 14 with the threaded portion 16 screwed into the threaded hole 18 of the swash plate 17 the journal 14 is linked with the drive plate 11 by a hinge mechanism 19 a hinge arm 20 projects from the drive plate 11 rearwards toward the journal 14 the hinge arm 20 is formed with an arched elongate hole 22 extending curvedly in an arc a hinge arm 21 projects forwards from the journal 14 toward the drive plate 11 the hinge arm 20 is linked with the hinge arm 21 by a pin 23 received in the elongate hole 22 the pin 23 the elongate hole 22 and the hinge arms 20 and 21 constitute the hinge mechanism 19 the arched elongate hole 22 limits swing motion of the journal 14 the drive shaft 10 passes through a center hole formed in a front end wall 4b of the front housing 4 and a center hole formed in the cylinder block 2 the drive shaft 10 is supported by the front housing 4 through a front shaft bearing or radial bearing 24b disposed in the center hole of the front housing 4 and by the cylinder block 2 through a rear shaft bearing or radial bearing 24a disposed in the center hole of the cylinder block 2 a thrust bearing 25 is interposed between the drive plate.