Abstract: There is provided an operation device including a main body that has a top surface on which an operation unit is provided, and an opening/closing member that is provided to be openable and closable with respect to the top surface of the main body, around a rotation axis positioned in an edge portion of a first side of the main body. When the opening/closing member is opened, the main body is pushed up by abutment of at least a part of the opening/closing member and a placement surface. A thickness of the main body is reduced from the first side toward a second side opposite to the first side.