To secure strength and simplify working of roof truss members by abutting a contact part orthogonally projected for a fixing part fixed on one roof truss member to the other roof truss member, and fixing a tenon part projected on the contact part by a pin and the like inserted in the mortice of the other roof truss member.

The lower half of a tenon fitting 20 is inserted in the mortice 36 of a strut 11, and the fixing part 42 of a connection fitting 30 is fixed on the side of the strut 11 by a bolt and nut. At this time, the upper bolt 31 penetrates the tenon fitting 20, which is also fixed on the strut 11. The mortice 32 of one purlin 12 is covered on the tenon fitting 20 projected from the upper end face of the strut, the end of the purlin 12 is mounted on the upper end face of the strut 11, a drift pin 21 is driven into the side of the purlin 12, and the purlin 12 and the strut 11 are connected to each other. The mortice 33 of the other purlin 12 is covered on the tenon part 44 of the connection fitting 30, the end of the purlin 12 is mounted on the contact part 43 of the connection fitting 30, and the other purlin 12 and the strut 11 are connected by the drift pin 21.