Apparatus for inserting square pins into a printed circuit board wherein during one stroke of a master cylinder, each square pin is cut by a movable cutter in combination with a fixed cutter from an elongated square pin-forming wire held in a chuck. The square pin is held by the movable cutter and then is moved over a guide member and then is further transferred into the guide member in accordance with the movement of a push rod moved by a main slider actuated by the master cylinder. The square pin is finally inserted into a printed circuit board by further movement of the push rod.