To reduce cost by substituting a conventional driving chain for a thin and small driving chain and compress the direction of height of the whole tray feeding device.

This tray feeding device is composed of a pair of guide roller units 95 whose chain guide 9 of the driving chain 7 is assembled by a base 91, a pair of guide rollers 92, 93, and a base support member 94 and an inner turn rail 96 and an outer turn rail 97 engaging and guiding each guide roller unit 95. Grade of about 26 degrees is provided for the horizontal direction on engaging faces of the guide rollers 92, 93 and the rails 96, 97.