A sheet folding apparatus comprises a feed roller mechanism consisting of a pair of roller adapted to feed a sheet clamped therebetween, a working roller mechanism mounted on the outlet side of the feed roller mechanism consisting of a central roller, a press roller in press contact with one side of the central roller, and a shift press roller in press contact with the other side of the central roller, and a shift guide mechanism mounted between the feed roller mechanism and the working roller mechanism. The shift press roller of the working roller mechanism is held for shifting movement between a first or access position where it is opposed to the press roller and a second or shifted position where it is in press contact with the other side of the central roller, along an outer peripheral surface of the central roller in a condition remaining in press contact with the central roller. The shift guide mechanism includes a pair of guide plates defining a sheet passage, and is shiftable between a normal position and a shifted position in operative association with the shift press roller. The apparatus can fold a sheet a plurality of times.