An actuator includes a frame-shaped first mass portion; a supporting
portion that supports the first mass portion and takes the shape of a
frame so as to surround a perimeter of the first mass portion; a pair of
first elastic portions coupling between the first mass portion and the
supporting portion so that the first mass portion is supported by the
supporting portion; a second mass portion provided inside the
frame-shaped first mass portion; a pair of second elastic portions
coupling between the second mass portion and the first mass portion so
that the second mass portion is supported by the first mass portion; and
a driver for rotating the first mass portion. The driver includes a
ferromagnet provided on the first mass portion in a position separate
from a rotation central axis of the first mass portion; a coil formed
along the rotation central axis of the first mass portion and the
supporting portion so as to surround and orbit a perimeter of the
ferromagnet if the first mass portion is seen from above; and a voltage
application unit for applying a voltage to the coil. An operation of the
voltage application unit included in the driver causes the coil to
generate a magnetic field. The generation of the magnetic field causes
displacement of the ferromagnet relative to the coil. The displacement of
the ferromagnet causes the first mass portion to rotate while torsionally
deforming the pair of first elastic portions. The rotation of the first
mass portion causes the second mass portion to rotate while torsionally
deforming the pair of second elastic portions.