A lens module includes a lens, a cam and an actuator. The lens has two driven parts disposed at one side of the lens. The cam is disposed beside the lens and has a rotation shaft and two cam surfaces, and a portion of the cam is located between the two driven parts. The two cam surfaces have the same shape and are on opposite sides of the cam. The two cam surfaces are in contact with the two driven parts respectively. The actuator is coupled with the rotation shaft and adapted to rotate the cam.