PURPOSE: To make it possible to install easily a master cut-off metal fitting in such a fashion that it may be directed to a spot to which a sleeve must be injected when embodying a horizontal sleeve injection construction method.

CONSTITUTION: A large number of guide pipes 1' whose both ends are closed, are buried and installed preliminarily in a specified area in an impervious wall so as to face a specified direction, using a construction time of a concrete-made impervious wall (b) in a shaft where at least on buried guide pipe is selected from among these buried guide pipes so that its base end may be exposed to the outside of the wall. After the base end of the buried guide pipe exposed to the outside is opened, and added guide pipe 4 is connected to the base end side while the added pipe 4 is supported and fixed on the impervious wall by way of an automatic control journal 5. A master cut-off metal fitting (a) is mounted and fixed at the tip of the fixedly supported added guide pipe 4.