To provide a strong polyhedron by preventing a polyhedron structural surface from being easily deformed and by improving the strength.

In a polyhedron whose ridge parts 1 are formed of frames F, respective polyhedron structural surfaces M are constituted by providing frame bodies 10 connected to side bodies 11 for constituting the sides of the polyhedron structural surfaces M, and each frame F is formed by joining the side bodies 11 of respective frame bodies 10 to each other. The front surface of the side body 11 of the frame body 10 is formed of a flat surface parallel to the polyhedron structural surface M, and the outer surface to which the side body 11 is joined is formed of the inclined surface inclined in relation to the front surface so that the angle of the mutually adjacent polygonal structural surfaces M may be the specified angle, and the outer surfaces of the side bodies 11 of the mutually adjacent frame bodies 10 are bonded through adhesives. Moreover, reinforcing members 20 to be buried in the side bodies 11 are provided on the connecting parts of the mutually adjacent side bodies 11 of the frame bodies 10.