A manual focusing mechanism, of an imaging apparatus provided with a lens system that includes a focusing lens group, which changes an image plane position by linearly moving the focusing lens group in an optical axis direction thereof via a manual operation of a focusing operational member includes a click-stop mechanism which holds the focusing operational member at one of a plurality of click-stop positions with respect to a support member. An amount of movement of the image plane position in the optical axis direction per one click-stop position of the focusing operational member via the click-stop mechanism is determined to be within a range of the depth of focus of the lens system of the imaging apparatus. An imaging apparatus having such a manual focusing mechanism is also disclosed.