To effectively vary damping force even in a low speed area of rod movement by securing a magnetic coil and a magnetically attracting members, which are magnetized due to the conduction to the magnetic coil and attracted to either a damper body member or a rod member, to either the damper body or the rod body.

A magnetic coil 12, which has a vertical coil axis line parallel with the axis line of a damper, is fitted and fixed to the part of a rod 4 to be inserted into an inner tube 2 at the cylindrical core 12a. A plurality of magnetically attracting members 13, which are split in the peripheral direction, are secured slidably in the cross direction of the damper in the ring-like groove of each yoke section 12b of this core 12a. Even while the rod 4 is moving at a normal speed in a low speed area, damping force can effectively be varied with good responsiveness by turning on and off the conduction to the magnetic coil 12.