PURPOSE: To avoid an excess load of a roof and to perform a large scale by selecting a part having sufficient durable strength of a building, obliquely erecting load supporting frames of front and back face sides on the part, coupling the tops, and self-supporting them to each other in an inverted V shape.

CONSTITUTION: Load supporting frames 2, 3 are formed similarly at both front and back face sides, and formed by assembling upper, lower and right, left aluminum frame members 5, 6 of relatively large thickness in four sides. The lower ends of the frames 2, 3 are clamped on a structural material having high durable strength such as existing girder, beam, etc., with hinge hardware 15. The frames 2, 3 of the front and back face sides erected obliquely oppositely are coupled at the tops by coupling hardware 16 inserted laterally to be supported in an inverted V shape. On the other hand, adjacent right and left load supporting frames are pipe-coupled at collectors 8, an intermediate 18 is interposed to be held between adjacent right and left frame members 6, coupling coating plates 19 are attached to be coupled watertightly.