Lens barrel

A lens barrel, comprising:

• a substantially cylindrical first frame that holds a lens, the first frame including an image plane side and a subject side in relation to an optical axis direction;
• and
• a substantially cylindrical second frame having an inside diameter and which is disposed in a state of encircling an outer peripheral surface side of the substantially cylindrical first frame on the subject side,
• the first frame has a protrusion on the image plane side, the protrusion extending outward in a radial direction from an outer peripheral surface of the first frame,
• the first frame and the second frame are formed so that a gap is formed on the image plane side between the outside diameter of the first frame and the inside diameter of the second frame at a position opposite the protrusion in the radial direction,
• whereby a distance between the outside surface of the first frame at the gap and an outermost surface of the protrusion in a direction orthogonal to the optical axis is less than the inside diameter of the second frame,
• a diameter of the outer peripheral surface side of the first frame on the subject side is less than the inside diameter of the second frame, and
• the inside diameter of the second frame is less than a sum of the diameter of the outer peripheral surface side of the first frame on the subject side and an amount by which the protrusion extends radially from the outer surface of the first frame on the image plane side.