A paper feed device and method for separating sheets of paper one by one from the bottom of a stack of paper loaded on a paper loading tray and for feeding the separated paper sheets consecutively. The feed device includes a rotatable hollow cylinder having a peripheral surface positioned below and close to the front end of the paper loading tray in the direction of paper sheet feed, and having an opening for drawing a paper sheet against the peripheral surface by vacuum suction. The vacuum suction is variable to set the suction pressure at the low level at the start of a paper sheet feed operation by the cylinder means, and if, after the predetermined time interval, the passage of the paper sheet is not detected, the vacuum suction pressure is increased to a higher level and maintained at the higher level to feed successive paper sheets. A paper sheet front end sensor, a conveyor, and a timer for setting a predetermined time interval after the start of a paper sheet operation, are also provided.