An optical device includes an elastic support portion which includes a torsion bar which extends along a second direction perpendicular to a first direction and a nonlinearity relaxation spring which is connected between the torsion bar and a movable portion. The nonlinearity relaxation spring is configured so that a deformation amount of the nonlinearity relaxation spring around the second direction is smaller than a deformation amount of the torsion bar around the second direction and a deformation amount of the nonlinearity relaxation spring in a third direction perpendicular to the first direction and the second direction is larger than a deformation amount of the torsion bar in the third direction while the movable portion moves in the first direction. A comb electrode is disposed along an outer edge of the movable portion.