Abstract: A feeder for use in a sheet-feed printing machine, in which, while a pile board loaded with a paper sheet pile on a pallet is moved upward, paper sheets are fed to the printing unit through a side register lay, comprising a sensor movable along a threaded shaft according to the rotation of the threaded shaft to detect a side edge of the paper sheet pile, which is moved an amount equal to the distance in the cross or lateral direction between a position at which the paper sheet pile is to be positioned when a left-pulling side register lay is used and a position at which the paper sheet pile is to be positioned when a right-pulling side register lay is used, and further comprising a non-interrupting paper replenishing device to insert another paper sheet pile under the paper sheet pile, or detecting means to detect the remaining amount of paper sheets and the top surface of the paper sheet pile.