A knee joint stimulation device that can effectively stimulate a knee joint is composed of a base, a frame provided upright on the base, a center shaft provided at an upper part of the frame, a crank connecting a motor and the center shaft and driven by rotation of the motor, a swing arm hanging down perpendicularly from the center shaft, and a support plate unit provided at a lower end of the swing arm and allowing a user in a sitting position to put his/her sole thereon. With the user putting the sole on the support plate unit, the length of the swing arm is adjusted such that a pivot point of a knee joint of the user is aligned with the center shaft.
