In an image-forming device including an image-carrying member, a developer-carrying member, and a casing having an inner space in which developer is accommodated and the developer-carrying member is supported, both a pushing force and a separating force are not applied to the casing so that the thickness of the casing does not need to be increased. An upper connector is provided and configured for connecting the body to an upper portion of a swimmer, in use. The slidable member is slidably positionable on the base member.