An actuator used for a camera module and controlling a lens assembly to move along an optical axis, includes a magnet disposed on a side of the lens assembly, a coil part disposed within a magnetic field of the magnet and controlling an up-and-down movement of the lens assembly when an electric power is applied, and a yoke part disposed to horizontally move the magnet disposed on the side of the lens assembly. The lens assembly is provided with a friction-generating member generating a frictional force to the lens assembly in an opposite direction to a direction in which the lens assembly moves to the yoke part.