A sheet feeding apparatus includes a tray, a driving mechanism disposed above the tray, a separating mechanism rotatably connected to the tray, and at least one resilient element to provide a constant pressure against the separating mechanism. The driving mechanism includes at least one roller to move one of the sheets. The separating mechanism includes at least one retard pad to separate the sheets and create frictional resistance between the separating mechanism and the stack of the sheets. When the tray has only a few sheets left, the separating mechanism is rotated and the frictional resistance is reduced.