An actuator according to example embodiments may be relatively compact and may be driven with 2 degrees of freedom with less spatial constraints. The actuator may include a base member, a ball screw member including a ball screw coupled to the base member and a ball nut screwed onto the ball screw, a driving member coupled to the ball nut so as to move in conjunction with the ball nut, a first directional displacement member configured to move in a first direction in response to a first movement of the driving member, a wedge member coupled to the driving member so as to be moved in a second direction in response to a second movement of the driving member, a second directional displacement member configured to move in a second direction in conjunction with the wedge member, and a binding member configured to bind the first directional displacement member to at least one of the driving member, the wedge member, and the base member.