PURPOSE: To construct a hip roof by eliminating hip rafter beams arranged at a crossing part of a hip roof and a main roof by using a trapezoidal beam at the hip roof part.

CONSTITUTION: An oblique member 9 is formed so as to incline by the angle equal to the slope of the roof and to have the length corresponding to the length of the roof in its arranged position. An inverted flat V-letter shaped beam 8 is constructed by welding a horizontal member 10, which has the length of one half of the horizontal length of the hip roof A in the arranged position, to the end of the oblique member 9. Trapezoidal beams 1 and 2 are constructed by connecting two of the inverted flat V-letter shaped beams 8 butting them at the end part of the horizontal member 10. The trapezoidal beams 1 and 2 are arranged in the preset hip roof part A and oblique beams 4 and 6 are arranged between girders 3 and the trapezoidal beams 1, 2. The oblique beams 4, 6 and a ridge beam 5, which constitute a main roof B, are arranged. A roof is constituted by connecting panels 7 to these beams.