To provide a roof structure of fine appearance with which ventilative circulation of the outdoor air and indoor air can be made in good performance.

A draft gap 2 is formed in the direction of the ridge of a roof structural such that roof board A is laid on an underlay material (a), and bridging support tools 3 attached to the left and right ridge portions 1', 1' are laid in line at a certain spacing in such a way as straddling the draft gap 2. Columns 4 are installed upright in line in the ridge direction on the ceiling parts 3' of the support tools 3, and ridge decorative supporting tools 5 are installed in line in the upper parts of these columns 4. A ridge decoration B furnished upright on the ridge 1 is secured by these supporting tools 5, and a ventilating structure for the internal and external air is formed in the ridge decoration B, and an external shutoff structure C or internal shutoff structure to prevent intrusion of rainwater is formed between the left and right outer bottoms of the ridge decoration B and an roof underlay material (a) or between the left and the right inner bottoms of the ridge decoration B and the bridging support tools 3.