To provide a tunnel prelining method which enables construction, to be performed even in the natural ground including the spring ground, and also serves as measures against spring water.

In the tunnel prelining method for excavating a tunnel 5 on the natural ground divided into the non-spring ground 1 and the spring ground 2, a perforated steel pipe 4A and a freezing pipe 4B are driven in the ground 1 and the ground 2 from the leading end 3 of an existing tunnel to be disposed as prelining above an excavation area. An improving body 6 is created by injecting a grout into the natural ground from the perforated steel pipe 4A, and the ground is frozen to form frozen soil 7 by introducing a refrigerating means into the freezing pipe 4B. These are formed above the tunnel 5 in an arch shape so that the construction doubling as the measures against the spring water can be performed in the ground 2.