The invention relates to a roof structure of a motor vehicle, comprising a front roof cross member and an intermediate roof cross member located behind the front cross member, said cross members extending in the transverse direction of the vehicle, the structure also comprising an equipment support connecting these cross members to one another approximately in the middle thereof, the support has, at a first end, indexing means that penetrate in the longitudinal direction of the vehicle into corresponding orifices provided in one of the cross members, these indexing means carrying out positioning in the transverse and vertical directions, while the first end cooperates in a bearing manner in the longitudinal direction with a vertical flank of said cross member, and the support has, at a second end, clip-fastening structures that carry out pre-retention in the vertical direction with the other cross member.