Abstract: A double action piston/cylinder unit has a piston guided in a cylinder and attached to a piston rod, the piston to be charged with a pressure agent, particularly hydraulic fluid at a first end face, the hydraulic fluid to be conducted in a controlled manner into the cylinder via a first fitting disposed at an end section of the cylinder and is to be charged at its other, second end face with a pressure agent which is located in an annular chamber formed by a central section of the piston rod and the inner wall of the cylinder, the second end face of the piston and a cylinder end piece, the annular chamber is in communication with a pressure agent reservoir which is connected to the annular chamber via a second fitting disposed at the other end section of the cylinder.