In a first step, a roof panel and a front header are joined at plural frictional spot joint portions at a front-end frictional joint area, and the roof panel and a rear header are joined at plural frictional spot joint portions at a rear-end frictional joint area. The roof panel and a side roof rail are joined at plural frictional spot joint portions at left-side and right-side frictional joint areas. Subsequently, in a second step, the members are joined at the plural rivet joint portions at a border area of the above-described joint areas, and the members are joined at plural rivet joints at a bounder area of the above-described joint areas. Accordingly, there can be provided a joining method and structure of metal members that can properly reduce deformation due to a thermal strain.