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 (161, 163) which is provided to the base and includes a plurality of first comb fingers (161a, 163a); and a second comb electrode (162, 164) which is provided to at least one of the movable portion and the elastic support portion (14, 15) and includes a plurality of second comb fingers (162a, 164a) alternately arranged with the plurality of first comb fingers (161a, 163a), wherein the elastic support portion (14, 15) includes a torsion bar (147, 157, 148, 158) extending along a second direction perpendicular to the first direction, wherein the first comb finger (161a, 163a) and the second comb finger (162a, 164a) which are adjacent to each other face each other in the second direction characterized in that the elastic support portion (14, 15) includes a nonlinearity relaxation spring (149, 159) connected between the torsion bar (147, 157, 148, 158) and the movable portion, wherein the nonlinearity relaxation spring (149, 159) is configured so that an absolute value of a twist angle of the nonlinearity relaxation spring (149, 159) around the second direction is smaller than an absolute value of a twist angle of the torsion bar (147, 157, 148, 158) around the second direction and an absolute value of bending of the nonlinearity relaxation spring (149, 159) in a third direction perpendicular to the first direction and the second direction is larger than an absolute value of bending of the torsion bar (147, 157, 148, 158) in the third direction while the movable portion moves in the first direction. 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 (161, 163) which is provided to the base and includes a plurality of first comb fingers (161a, 163a); and a second comb electrode (162, 164) which is provided to at least one of the movable portion and the elastic support portion (14, 15) and includes a plurality of second comb fingers (162a, 164a) alternately arranged with the plurality of first comb fingers (161a, 163a), wherein the elastic support portion (14, 15) includes a torsion bar (147, 157, 148, 158) extending along a second direction perpendicular to the first direction, wherein the first comb finger (161a, 163a) and the second comb finger (162a, 164a) which are adjacent to each other face each other in the second direction characterized in that the elastic support portion (14, 15) includes a nonlinearity relaxation spring (149, 159) connected between the torsion bar (147, 157, 148, 158) and the movable portion, wherein the nonlinearity relaxation spring (149, 159) is configured so that an absolute value of a twist angle of the nonlinearity relaxation spring (149, 159) around the second direction is smaller than an absolute value of a twist angle of the torsion bar (147, 157, 148, 158) around the second direction and an absolute value of bending of the nonlinearity relaxation spring (149, 159) in a third direction perpendicular to the first direction and the second direction is larger than an absolute value of bending of the torsion bar (147, 157, 148, 158) in the third direction while the movable portion moves in the first direction.