To mount a chain at a prescribed position with comparatively little man-hour without requiring a complicated work by using comparatively few members having simple shapes.

A main body 21 of a chain mounting device 9 surrounds four link plate groups 8bA, 8aA, 8bB and 8aB each of which is constituted of a plurality of link plates 8a or link plates 8b. The remaining link plate groups are derived to the outside of the main body 21 from a chain insertion port 24. In the main body 21, the chain 8 is bent at two connecting parts. A slip-out prevention pin 22 is mounted on a lower side of the main body 21. Even if the chain 8 is pulled to an upper side, the link plate groups 8bA, 8aA, 8bB and 8aB are not capable of going to the outside of the main body 21 by being regulated by an upper wall part 21a, a front wall part 21b and a rear wall part 21c of the main body 21.