A damping force controller of a motorcycle shock absorber enables the motorcycle to jump high when needed in a stabilized attitude and to run downhill in a stabilized manner while preventing the rear wheel from bouncing. The damping force controller of a motorcycle shock absorber is adapted to regulate the damping force, wherein the extension damping force of the rear wheel shock absorber at the moment at which the vehicle is beginning to jump is regulated to be smaller than the extension damping force for a normal run.