The optical device of the present invention includes an optical element; a first holding member that holds the optical element; and a second holding member that holds the first holding member via a plurality of connections, and has a linear expansion coefficient different from that of each one of the optical element and the first holding member. When the plurality of connections are displaced upon receiving a force depending on the difference of the linear expansion coefficients between the first holding member and the second holding member, the first holding member causes the connection to the optical element to be displaced in a predetermined direction different from the displacement. The predetermined direction is the opposite direction of a force received by the connection between the optical element and the first holding member, depending on the difference of the linear expansion coefficients between the optical element and the second holding member.