PURPOSE: To simply and quickly construct a formwork.

CONSTITUTION: A rail 12 for reference guage is set on a given position for leveling, the groove 28 of a formwork 16 of a cement board with PC steel bars is fitted on the rail 12 and temporarily fixed by a temporary stop metal 52. The formwork 16 is fixed by a bracket 32 and bolts 30. The formworks 16 adjacent in the horizontal direction are connected by connecting metals 22 and 24 to set the formworks 16 in order from the lowermost stage to the upper stage. A white wash leakage-preventing packing 42 is attached to the vertical edge of the formwork 16, and space between the formworks 16 is closed by a plate formwork 40. They are fixed by a rod 44, a press metal 46, a clamp metal 48, and a form tie 50. The production cost of the formwork can be obtained at low cost by extrusion molding in a short time by lessening the use of temporary materials and by using no wooden material. A prestress is applied to the formwork to greatly raise the bending strength of it.