PURPOSE: To permit the height of formwork to be adjusted freely by a method in which a moving face plate is provided on the formwork base, the angle side wall of formwork is set on both ends of the middle of the formwork base, a bottom face plate is provided between the side walls of formwork, face plate side walls are provided on tips of side walls of formwork, and face plate tip walls are provided along the tip of the moving face plate.

CONSTITUTION: According to the height of retaining wall, the length of face plate tip wall 12 and bottom face plate 7 in a moving face plate 4 is adjusted, and face plate side walls 10 are connected by fixing handles 13 provided on both sides of the wall 12. A formwork A for wall decoration is inserted from the rare of the formwork base 1 into an opening 9 through which the formwork A is taken out and set on the plate 4. Concrete is placed onto the plate 4 and covered with an inner face plate 14 and the inside of the angle side walls 6 of formwork is covered with inner face plate 14. Concrete is then placed from the upper end and cured sufficiently, the plates 14 are removed, and the connection between the side walls 10 and the tip wall 12 is released to open them outwards. The formwork A is pulled out from the opening 9 bakwards.