An optical device comprising: a base; a movable portion which includes an optical function unit; an elastic support portion (14, 15) which is connected between the base and the movable portion and supports the movable portion so that the movable portion is movable along a first direction; a first comb electrode which is provided to the base and includes a plurality of first comb fingers; and a second comb electrode which is provided to at least the movable portion and includes a plurality of second comb fingers alternately arranged with the plurality of first comb fingers, wherein the elastic support portion (14, 15) includes a first torsion bar extending along a second direction perpendicular to the first direction, a nonlinearity relaxation spring connected between the first torsion bar and the movable portion, a second torsion bar, and a first lever connected to the movable portion through the first torsion bar and connected to the base through the second torsion bar, wherein the nonlinearity relaxation spring is configured so that an absolute value of a twist angle of the nonlinearity relaxation spring around the second direction is smaller than an absolute value of a twist angle of the first torsion bar around the second direction and an absolute value of bending of the nonlinearity relaxation spring in a third direction perpendicular to the first direction and the second direction is larger than an absolute value of bending of the first torsion bar in the third direction while the movable portion moves in the first direction, and wherein the second comb electrode is disposed along an outer edge of the movable portion. a base; a movable portion which includes an optical function unit; an elastic support portion (14, 15) which is connected between the base and the movable portion and supports the movable portion so that the movable portion is movable along a first direction; a first comb electrode which is provided to the base and includes a plurality of first comb fingers; and a second comb electrode which is provided to at least the movable portion and includes a plurality of second comb fingers alternately arranged with the plurality of first comb fingers, wherein the elastic support portion (14, 15) includes a first torsion bar extending along a second direction perpendicular to the first direction, a nonlinearity relaxation spring connected between the first torsion bar and the movable portion, a second torsion bar, and a first lever connected to the movable portion through the first torsion bar and connected to the base through the second torsion bar, wherein the nonlinearity relaxation spring is configured so that an absolute value of a twist angle of the nonlinearity relaxation spring around the second direction is smaller than an absolute value of a twist angle of the first torsion bar around the second direction and an absolute value of bending of the nonlinearity relaxation spring in a third direction perpendicular to the first direction and the second direction is larger than an absolute value of bending of the first torsion bar in the third direction while the movable portion moves in the first direction, and wherein the second comb electrode is disposed along an outer edge of the movable portion.