To recover the strength and neutralization of concrete and reinforce the deteriorated surface layer of the concrete to improve the quality of the concrete itself by uniformly and securely filling a medicine deeply to portions made fragile by crazing and cracking by alkali-aggregate reaction, reinforcement corrosion by salinity, phytotoxicity of the other concretes, and acid rain.

A sheet 2 of anti-alkali laminated structure with a specified width is wrapped around the portion 3 of a concrete surface coming into contact with the periphery of a construction district beforehand. The entire surface of a sheet 2 is coated with an anti-alkali patty-like resin 4 with a spatula. The putty-like resin is extruded by approximately 20 mm from the end parts of the sheet, and the entire surface of the sheet of the laminated structure is fixed to the concrete surface. After the putty-like resin is hardened, lithium nitrite is filled through a filling pipe 1 pre-mounted on the sheet of the laminated structure to gradually penetrate it into the concrete.