A deck cross-member comprises a first pipe, a joint member, and a second pipe. The first pipe is configured to support a steering unit. The first pipe has a cross section that is uniform along the axial direction as viewed in a plane perpendicular to the axial direction. The joint member is inserted in the first pipe and secured to the first pipe. The joint member incorporates a receptacle unit. The second pipe is inserted in the receptacle unit of the joint member, thus secured to the joint member. The second pipe has a cross section that is uniform along the axial direction as viewed in a plane perpendicular to the axial direction.