A chain delivery sheet feeding device, including a sheet size selector switch for selecting a desired sheet size among paper sheets of different sizes which are separately carried on a plural number of paper trays located within the apparatus. A plurality of grippers are provided on chain members for gripping the paper sheets. A sheet releasing device is also provided for separating the paper sheets from the grippers. The sheet releasing device comprises a switching member having a movable gripper-releasing cam member which is adapted to operate under the control of a solenoid device which determines the sheet releasing point for the grippers. A size selector switch and the sheet releasing point determining solenoid device are opreated in relation to each other by means of a delay circuit in such a manner that a current sheet releasing point is retained until the last one of a number of copy sheets for a preceeding original size is released.