Lens unit

A lens unit including an optical system having a plurality of lenses, the lens unit comprising:

• a correction lens forming a part of the plurality of lenses and having an optical axis, and configured to correct movement of a focus position of the optical system caused by a temperature change by being moved in a direction of the optical axis;
• a holding frame holding the correction lens;
• a stationary tube movably supporting the holding frame along the direction of the optical axis;
• at least one movement guide portion provided between the stationary tube and the holding frame in a radial direction of the stationary tube, and configured to limit rotation of the holding frame in a direction intersecting with a plane orthogonal to the optical axis and to guide movement of the holding frame in the direction of the optical axis by being in contact with at least one of the stationary tube and the holding frame;
• a plurality of heat deformed members provided between the stationary tube and the holding frame in the direction of the optical axis, arranged in a circumferential direction of the stationary tube, and configured to change a distance between the holding frame and the stationary tube along the direction of the optical axis by deformation associated with the temperature change;
• and
• a first biasing means configured to relatively bias the holding frame against the stationary tube via the at least one movement guide portion in the radial direction of the stationary tube.