An actuator 100 includes: a pair of driving portions 1, 11 spaced apart from each other; a movable portion 2 provided between the pair of driving portions 1, 11; a pair of supporting portions 3, 3 for supporting the pair of driving portions 1, 11 and the movable portion 2; a pair of first elastic connecting portions 4, 4 which respectively connect the pair of driving portions 1, 11 to the pair of supporting portions 3, 3 so that each of the driving portions 1, 11 can rotate with respect to the supporting portions 3, 3; and a pair of second elastic connecting portions 5, 5 which respectively connect the movable portion 2 to the pair of driving portions 1, 11 so that the movable portion 2 can rotate in accordance with the rotation of the pair of driving portions 1, 11. In this case, each of the pair of driving portions 1, 11 rotates around a rotation central axis 41 of the actuator 100 by application of an alternating voltage, whereby the movable portion 2 rotates around the rotation central axis 41 of the actuator 100. Further, the torsional rigidity of each of the first elastic connecting portions 4, 4 is larger than that of each of the second elastic connecting portions 5, 5.