Shock absorber

A shock absorber, comprising:

• N magnets arranged such that like poles of adjacent magnets face each other to generate repulsive force, where N is an integer of at least 2;
• a magnet holder that accommodates the N magnets in absorbing direction such that a distance between the adjacent magnets is variable so that the shock absorber absorbs a shock applied to two end magnets disposed at respective ends of the N magnets;
• a coil unit including at least one electromagnetic coil located on at least either of an outer circumference part and an inner circumference part of the N magnets bank;
• and
• a controller that controls an electrical operation of the coil unit including a drive controller and a power storage controller, wherein the drive controller performs a drive control operation of supplying electric current to the coil unit to vary a shock-absorbing performance of the shock absorber, wherein the power storage controller performs a power storage control operation by using electric power generated in the coil unit caused by movement of at least one magnet out of the N magnets,
• wherein the controller executes a changeover between the drive control operation and the power storage control operation, and provides a short rest interval time between the drive control operation time and the power storage control operation time.