The present invention provides a defect-less and easy to operate power actuated piston tool with automatic piston return, designated for driving fasteners into a base like masonry, concrete, wood or the like. The tool according to the invention is characterized by that on piston shank (11) of piston (1), there is an elastic returning bush (7), situated between piston head (12) and fastener guide (5), said returning bush (7) is a one-piece in shape of bellow, made of elastomeric material, of regularly variable diameter.
