A paper folding apparatus includes a ruling unit that rules a line on each of sheets, a pushing unit that pushes the sheets on which the lines are ruled by the ruling unit, and a pair of folding rollers that comes into contact under pressure with the sheets pushed by the pushing unit and discharges the sheets. The ruling unit includes a plurality of pressing blades for ruling a line on each of the sheets, a swinging unit that swings the pressing blades from a pressing position where the pressing blade presses the sheets to a retracted position where the pressing blades are retracted from the sheets, and a moving unit that moves the pressing blades and the swinging unit along the sheets.