A first leading end plate and a first rear end plate are provided at an upper part of a rotary table. When a conductor piece contacts the first leading end plate, a first contact detection sensor detects a contact of the conductor piece, and transmits a contact detection signal to a storage control unit. Upon receiving the contact detection signal, the storage control unit drives an air supply device for a predetermined period to spray air toward the conductor piece from a first air nozzle. The air spray brings the conductor piece into a tilted state with the rear end thereof moved downward. Even when the conductor piece contacts the first leading end plate and rebounds, the rear end thereof contacts an inner wall surface of the first rear end plate, thereby preventing the rear end of the conductor piece from getting over the first rear end plate.