The invention relates to a working cylinder comprising a cylinder unit with a front end part (4), a rear end part (15) and a cylinder tube (12) connecting these end parts, a piston (5) movable in the cylinder tube (12) and a piston rod (1) secured to the piston and extending through the front end part (4). The purpose is to provide a novel, simple solution for securing the cylinder tube (12) to the end parts (4, 15). Each end part (4, 15) has a shoulder (18, 16), the cylinder tube (12) being connected to each end part (4, 15) by means of a compression ring (13, 14) which upon deformation of the end of the cylinder tube (12) and by means of said end tightly clamps the end shoulder (18, 16).