PURPOSE: To improve the general use of an automobile shock absorber by inserting a hollow rod, formed by disposing hollow pipes in multiple layers through insulators and forming spaces among the hollow pipes into control spaces, into a cylinder through a piston, then forming the respective pipes into alternately opposite electrodes, and communicating the control spaces with a piston side chamber and a rod side chamber.

CONSTITUTION: A hollow piston rod 3 is formed by connecting plural hollow pipes 4a-4c in layers by insulating connecting plates 10a, 10b, and spaces among the pipes 4a-4c are formed into control spaces S. These control spaces S are communciated with a piston side chamber R1 through the hollow part A of the pipe 4c, the hollow part B of the insulating member 10b, the hollow part C of a connecting plate 11 and the hollow part D of a nut 12, and also communicated with a rod side chamber R through the communicating hole 3d of the piston rod 3. The pipes 4a-4c are alternately formed into one electrode and the other electrode, and voltage is applied to both electrodes to perform the change control of viscosity of an electroviscous fluid.