A rehabilitation device for lower limbs was developed. It aims a fusion of a rehabilitation machine and an amusement machine to stimulate the mental aspect of the subjects. It can be used as an amusement machine rather than an exercising machine for ordinary people. The machine simulates the motion of a log floating on the water. It is composed of a roller made of wood, some actuators and a personal computer as a controller. The roller is connected to a brake by which the rotation torque can be controlled according to the level of the locomotion of the subject. Either side of the roller can be moved up and down independently to simulate the motion of a log being tossed about by the various waves. The subject is supported in a special outfit for the sake of safety and unweighing.