Linear actuator

A linear actuator in which a slide table is made to move reciprocally along an axial direction of a cylinder main body, comprising:

• a guide mechanism comprising a guide block attached to the cylinder main body and in which circulation grooves are formed through which a plurality of rolling bodies roll and circulate, and a cover member disposed on an end of the guide block, the guide mechanism guiding the slide table along an axial direction of the cylinder main body;
• and
• a retainer installed on the guide block, for retaining the rolling bodies freely circulatable in the circulation grooves, and for retaining the cover member with respect to the guide block,
• wherein the circulation grooves are formed to open in the guide block along a longitudinal direction thereof, and the retainer is disposed detachably with respect to the guide block.