To perform the miniaturization, weight saving and cost reduction of a segment fastening device by securing an indentation load of a cotter for fastening a segment in the segment fastening device.

In an erector device 21, the cotters 14, 15 within a cartridge 61 are held by holding levers 67, 68 of the segment fastening devices 51, 52. The cotters 14, 15 are inserted from the side of a cutting face into an engaging groove 11 formed along the longitudinal direction of a tunnel in the end surfaces of the segments first, and then a pressing part 77 of a press-in jack 76 presses the cotter 14, 15 and makes engaging parts 14a, 15a engaged to engaging grooves 12a, 13a of cotter fittings 12, 13 for the purpose of fastening the segments while a reaction receiving jack 79 extends to make the end part of a driving rod 80 abut on a ring girder 81 and gains reaction from a basic machine 22.