PURPOSE: To enhance workability and reliability, and lighten weight, and improve durability by arranging vertical channels and horizontal channels on the one surface of a PCa board, to form salient section groups, and to enhance the jointing performance of cast-in-place constructed sections on the board surface, and to form the constructed sections integrally, and by enabling hollow section to be formed with the combinations of permanent forms to be arranged on the deep channel sides.

CONSTITUTION: On the one surface of a PCa board 2 reinforced with arranged reinforcements 3, a plurality of vertical channels 5 and horizontal channels 6 are arranged vertically and horizontally at intervals, and the groups of salient sections 8 are formed. Besides, on the PCa mold to be served also for a structural body, permanent forms 9 to be arranged on the deep channel sides of the vertical channels 5 or the horizontal channels 6 and for forming hollow sections S in the internal sections of the deep channels are combined with each other.