PURPOSE: To use a wire netting plate having a mesh form capable of preventing the outflow of placed concrete in a sheathing board, and dispense with the removal of the sheathing board at form release.

CONSTITUTION: Angle members 10A are raised at prescribed intervals on a foundation concrete A for land slide protection. A wire netting plate 20 is put thereon, angle members 10B are horizontally provided so as to cross it in grid, and the wire netting plate 20 is nipped between both the angle members 10A, 10B. A connecting member is inserted and fixed to both the angle members 10A, 10B and the wire netting plate 20 so that the dropping out can be prevented to form a mountain-side sheathing board B for a placing form C. A sheathing board D opposed to the wire netting plate 20 is also provided to form the placing form C, and concrete is placed thereto. At form release, the wire netting plate 20 is not removed but buried in the sand and earth as it is to construct a land slide protection.