Abstract: A pressure cylinder comprises a cylinder housing with a cylinder space in which a fitting piston is axially movable. A piston rod (1) of a composite material extends from the piston. The piston rod (1) comprises a layer of core material under a surrounding outer jacket. The layer of core material (3) is constructed from composite material fibres oriented parallel to a longitudinal axis of the piston rod and straightened, and the outer jacket (5) is constructed from composite material fibres wound at an angle relative to the longitudinal axis. Thus provided is a pressure cylinder with a piston rod (1) of relatively light weight, which can withstand a relatively high pressure load. Less composite material is hereby required for the piston rod (1) while the strength remains the same.