Feeder

A feeder characterized by comprising a forward winder which rotates forwardly and reversely, a reverse winder which rotates forwardly and reversely, a forwardly winding linear body to be wound and rewound through said forward winder, a reversely winding linear body to be wound and rewound through said reverse winder and a reciprocating body to forwardly and reversely move by means of guide means when it is subject to a forward force or a reverse force and wherein said forwardly winding linear body to be held so as to be wound and rewound by said forward winder and said reversely winding linear body to be held so as to be wound and rewound by said reverse winder are connected to said reciprocating body, said forward winder on winding rotation and said reverse winder on rewinding rotation rotate in synchronism and phase with each other in the winding and rewinding directions, respectively, said forward winder on rewinding rotation and said reverse winder on winding rotation rotate in synchronism and phase with each other in the rewinding and winding directions, respectively, the amount of winding said forwardly winding linear body by said forward winder and the amount of rewinding said reversely winding linear body by said reverse winder are equal to each other and the amount of rewinding said forwardly winding linear body by said forward winder and the amount of winding said reversely winding linear body by said reverse winder are equal to each other.