A cylinder body includes a first guide surface made up from first guide grooves and a first bulging portion, wherein a slide table is displaceably supported on the first guide surface via a guide mechanism. Additionally, guide members of a guide block that constitutes the guide mechanism are inserted into and fixed within the first guide grooves. Further, the cylinder body is equipped with a second guide surface, which is formed with substantially the same shape as the first guide surface. In the event that the first guide surface is oriented upwardly and the slide table is installed thereon, the second guide surface acts as a mounting surface, whereas, in the event that the second guide surface is oriented upwardly and the slide table is installed thereon, the first guide surface acts as the mounting surface.