PURPOSE: To safely, easily and aerially convey a plurality of pipe members on air by fitting a small bore inner pipe into a large bore outer pipe, by clamping their opposite ends with common clampers, by fastening fasteners provided to the clampers, and thereafter by hoisting and holding them with the use of a suspender.

CONSTITUTION: During installation of various pipe lines in a base, an inner pipe member B such as a sediment preparing filler pipe is fitted in an outer pipe member A such as a steel pipe used in an excavating and mud-discharging machine or the like for a sediment pressure shield tunneling method so as to convey them as duplex pipes. In this case, opposite ends 17, 18, 17', 18' of both pipe members A, B are fixed and held by clampers 6. Each of these clampers 6 is formed in a bifurcated shape (U-like shape), having a first branch 2 and a second branch 4 adapted to abut against the outer peripheral surface 1 of the outer pipe member A and the inne peripheral surface 3 of the inner pipe member B, and a curved coupling part 5 coupling them. A fastening part 12 to which a nut 7 screwed onto a bolt 11 incorporating a wrench shaft is secured is provided at the front end of the first branch 2. Further, a protrusion 21 for pressing the outer peripheral surface of the outer pipe member A is formed, if necessary, on the intermediate part of the first branch 2.