PURPOSE: To reduce the mounting space of a strut through prevention of a rolling diaphragm, and to decrease weight and a cost, by a method wherein th sectional shape of the cylinder of the strut is formed in the shape of a circle which is non-concentric to the center of a piston rod.

CONSTITUTION: The lower end of a cylinder 11 is securely attached to a spindle 12 supporting a steering wheel, and a piston 14 is slidably engaged with inwardly with an inner cylinder 11a of the cylinder 11. Relatively vertical movement of the piston 14 to the cylinder 11 causes generation of a damping force. The lower end of a piston rod 15 is fastened to the piston 14, and the upper end is rotatably attached to a car body 19 through a bearing 17 and an insulator 18. The center of the piston rod 15 is positioned eccentrically from the center of the inner cylinder 11a, and this causes the inner cylinder 11a to be set so that it is formed in the shape of a circle which is non-concentric to the center of the piston rod 15, resulting in provision of the same rotary angle at all times.