To simultaneously obtain a composite tunnel liners by one circumference by integrating respective shells and a concrete by a method wherein the respective shells and a sheet are housed in a centrifugal molding drum, which is formed by putting the upper frame of the centrifugal molding drum on its lower frame and then connecting both the frames, so as to place concrete in the respective shells in order to execute an centrifugal molding.

A centrifugal molding drum 1 is assembled by fastening an upper frame 2 and a lower frame 3, both of which have shapes obtained by bisecting a cylinder by a plane containing its cylinder axis, with bolts 4 into the cylinder and then fitting casings 5 to both the end parts of the cylinder. This centrifugal molding drum 1 is rotated about a horizontal cylinder axis on a rotating device. Under the above-mentioned state, by placing concrete on the inner wall of the drum, a centrifugal force is given to the concrete, resulting in centrifugally molding a tunnel liner. In this case, a flexible plate-like sheet such as a rubber belt-like sheet having the longitudinal and lateral dimensions nearly equal to those of the inner peripheral surface of the centrifugal molding drum is used. By mounting the respective shells of the segments of a composite tunnel liner by one circumference on this sheet, this resultant sheet is inserted in the centrifugal molding drum 1.