To reduce a gap between an inside pushing slide pipe and the fitting part thereof to increase the water-sealing force of a sealing member by fixing a reinforcing plate forming a sealing groove at the front end of an inside pushing pipe and putting the sealing member therein.

A concrete pipe is covered with a cylindrical reinforcing plate 13 at the outer periphery and a reinforcing ring 15 and an end plate 18 are welded at the front end, and a sealing member 19 is put in the sealing groove 16 of the reinforcing ring 15, in the inside pushing pipe 11. An inside pushing slide pipe 12 is provided with an insert mouth 24 connecting a standard jacking pipe at the front end and a cylindrical fitting part 23 is slidably inserted from the outside of the inside pushing pipe 11 to bring the inner peripheral face thereof to close contact with the sealing member 19. An inside thrusting jack 29 is equipped in between a flange 25 and the end plate 18 to advance the forward standard jacking pipe. Pressure water is ejected from an ejecting hole 22 for washing water when it is required to reject soil in the gap of the fitting part 23 and reduce the sliding resistance. Accordingly the sealing member 19 is put in the sealing groove 16 to reduce the gap in the fitting part 23 and increase the water-sealing force of the sealing member 19.