a roof structure is disclosed which is capable of accomplishing an improvement in workability , ensuring safety in the assemblying operation and preventing leakage of rain . the roof structure is assembled by engaging an eaves side connection of ridge side one of each adjacent two roof boards with a ridge side connection of eaves side one of the roof boards and securely holding the eaves side and ridge side connections engaged together by means of a fixture fixed on a common rafter at a position on the eaves side beyond the eaves side connection of the ridge side roof board and securely held in the eaves side connection engaged with the ridge side connection .