To provide a support structure of a roof capable of facilitating installation of the roof panel and effectively using a habitable space.

The support structure of a roof supports an inclined roof Y constituted of a plurality of roof panels 20 with a cross frame member 16 provided between bundle members 11a. The cross frame member 16 is provided with a plurality of support materials 17 protruded to the both sides and a support material 18 respectively provided in each support material 17. The roof panel 20 is fixed to each support member 18.