A rehabilitation apparatus is disclosed. The rehabilitation apparatus includes a supporting housing, a rotary housing, an actuator, a control unit, and a torque detector. The rotary housing is slidably mounted to the supporting housing to hold a body segment. The actuator has a driving shaft to rotate the rotary housing. The control unit is electrically connected to the actuator to control the actuation of the actuator. The torque detector is electrically connected to the control unit, thereby detecting a torque exerted on the driving shaft, and transmitting a torque signal to the control unit.