A primary object of the present invention is to modify passiveness of a conventional soiling nailing method by using activeness of an earth anchor method. Another object of the present invention is to combine advantages of the conventional soil nailing method and earth anchor method to develop a new technology. In other words, a technology according to the present invention is a new technology having the following features. Firstly, a fixed length of the conventional earth anchor method is not required in a method according to the present invention because the length of a grouting body may act as a reinforcement element only with a length corresponding to a free length of the conventional earth anchor method. Secondly, although the free length of a coated wire is formed in the conventional earth anchor method, grout is injected to a pipe in the method according to the present invention, a reinforced grouting body is formed and resists a shear stress and thereby the pipe does not receive any tensile force due to a prestress.