To facilitate transportation and installation construction of cradle constitution members while maintaining strength of a cradle.

There is provided a cradle constitution system such that a plurality of muntins are arranged and fixed on a base part substantially in parallel and at a predetermined angle and planar articles such as solar panels are arrayed and fixed longitudinally and laterally on upper surfaces of the muntins. A muntin frame is used which comprises one unit on the whole while having the muntins arranged at an upper end thereof. A cradle is formed by arraying a plurality of muntin frames on the base part and suitably arranging and fixing reinforcing materials between the muntin frames. Consequently, the planar articles can be arrayed and fixed on the respective muntins of the cradle. The cradle may be constituted by forming ledge frames instead of the muntin frames, arraying at least two of the ledge frames in a front-rear direction, and mounting and arraying the plurality of muntins on the ledge frames.