LENS BARREL

PROBLEM TO BE SOLVED: To provide a lens barrel which permits further thinning in the collapsible state with a simple constitution. SOLUTION: The lens barrel 1 includes: a fixed frame 2; a rotation frame 3 which advances and retreats while being rotated in the optical axis direction with respect to the fixed frame 2; and a straight advance guide frame 4 which is arranged inside the rotation frame 3 and is displaced integrally with the rotation frame 3 in the optical axis direction in the rotational restraint state, wherein an engagement protrusion 3c disposed on the inner circumference of the rotation frame 3 is slidably fitted to a circumferential guide groove 4d disposed on the outer circumference of the straight advance guide frame 4 and the straight advance guide frame 4 is driven forwards and backwards in the optical axis direction O integrally for the rotation frame 3. The engagement protrusion 3c is inserted to a notch 4c disposed on the circumferential groove 4d and is engaged with the circumferential guide groove 4d and, further, such a structure that both of a front edge surface 4g of the straight advance guide frame 4 and a front edge surface 3g of the rotation frame 3 are exposed is used. COPYRIGHT: (C)2009,JPO&INPIT