The imaging device includes a camera body and an interchangeable lens unit detachably attached to the camera body, the imaging device including, an optical system including a focus lens, an infinite rotation type focus ring, a lens drive part moving the focus lens forward and backward in an optical axis direction of the optical system, a setting part allowing a user to set a rotation range of the focus ring, a storage part assigning and storing respective different rotation amounts of the focus ring to multiple positions within a movement stroke of the focus lens in accordance with a rotation range set in the setting part, and a control part driving the lens drive part to move the focus lens depending on a rotation amount of the focus ring to a position corresponding to the rotation amount stored in the storage part.