An actuator having a rotation central axis includes: an insulative frame;
movable comb electrodes having first electrode teeth; a movable portion
between the movable comb electrodes; supporting portions on the frame
supporting the movable comb electrodes and the movable portion; fixed
comb electrodes on the frame corresponding to the movable comb electrodes
and provided with second electrode teeth; first elastic connecting
portions connecting the movable comb electrodes to the supporting
portions so each movable comb electrode can rotate around the rotation
central axis; and second elastic connecting portions connecting the
movable portion to the movable comb electrodes so that the movable
portion can rotate around the rotation central axis. Each movable comb
electrode is driven by an alternating voltage between each fixed comb
electrode and movable comb electrode. Part of the first electrode teeth
overlaps part of the second electrode teeth when no alternating voltage
is applied.