An actuator with switchable releasing speed includes an actuation rod, a screw, and a motor. The motor drives the screw rotating so that the actuation rod axially moves relative to the screw. The motor includes a stator, a rotor, a plurality of commutators, and at least three brushes. The at least three brushes have a positive brush, a negative brush, and at least one auxiliary brush. The positive brush is connected to a positive DC voltage. One of the negative brush and the least one auxiliary brush is adjusted to connect to a negative DC voltage so as to change a rotational speed of the rotor, thereby controlling a movement speed of the actuation rod. Accordingly, the releasing speed of the actuator is switchable.