LENS BARREL

PURPOSE:To reduce a run-out phenomenon in an image caused by the movement of the principal point of a focus lens group by interposing an elastic member which moves and presses so that the linear contact of two annular members may be performed at a fixed position in a direction parallel with an optical axis between two annular members. CONSTITUTION:Between a fixed barrel 15 and a focusing ring 16 being two annular members fitting with each other, the elastic member 22 which moves and presses the focusing ring 16 in the previously fixed direction is interposed, so that the fixed barrel 15 is linearly brought into contact with the focusing ring 16 from the micro point of view such as viewing in fitting clearance. By bringing the fixed barrel 15 into contact with the focusing ring 16 at a linear contact part 23 by the force of the elastic member 22, the contact part 23 is not positionally moved when the focusing ring 16 is driven to be rotated through a pinion 20 and a gear 16a. Or even when it is moved, the moving amount of the principal point of the focusing lens group L1 is extremely small. Therefore, the run-out phenomenon in the image is prevented.