PURPOSE: To reduce noise from a drive device by shifting the inner edge parts of a pair of trays in a vertical direction with a shifting means 13, and forming a sheet introduction space expanded in an area to either of the trays to receive a sheet which is discharged from a copying machine.

CONSTITUTION: The outer edge parts 11 of a pair of sheet receiving trays 10 which are supported to a frame structure 1 are supported on a base supporting body 12 so as to travel pivotally, and their inner edge parts are disposed at the lower part of a shifting means 13 so as to be shifted in a vertical direction by the shifting means 13. With this constitution, a sheet introduction space 15 which is expanded in an area to either of the trays is formed to receive a sheet which is discharged from the outlet roll 17 of a copying machine. The shifting means 13 includes a tray transferring wheel 18 which is rotated by a driving motor 20 through a belt 21, and the inner edge parts of the trays are shifted by engaging a cut part 24 which is formed in the wheel 18 in a radius direction with cam followers or trunions 22 on the respective trays.