PURPOSE: To compact and miniaturize structure by forming respectively a piston rod in cylindrical shape and a damping piston in annular shape, and guiding the divided piston in an inner tube extending in the piston rod.

CONSTITUTION: A piston rod 3 in cylindrical shape and a damping piston 2 in annular shape are respectively formed, the piston 2 is surrounded with a slight peripheral clearance in an annular space formed between an inner tube 6 and a cylinder 1. Therefore the inner wall of the piston rod 3 is guided along the outer wall of the inner tube 6 through the whole stroke of the piston 2, so a high stability of the damper is realized. A floating piston 12 dividing the compensating chamber 11 is movably arranged in the inner tube 6, it at least partially separates a compensating chamber 11 from a pneumatic spring chamber 13 formed in the interior of the tube 6 in sealing tight manner.