A swashplate type hydraulic pressure device comprising a cylinder and a swashplate which is rotatable relative to the cylinder and rotatably supported on a holder, the cylinder having a number of plungers disposed thereon axially slidably in an annular arrangement, in which a spherical end is formed at that extreme end of each plunger which is in abutment with the swashplate, and the swashplate is provided with a spherical concave portion for engagement with the spherical end. By cooperation between the spherical concave portions and the ends, the cylinder rotates synchronously with the swashplate and an aligning action is imparted to the swashplate from the group of plungers of the cylinder.