Cyclic sewing device, method thereof, and sewing machine having the cyclic sewing device

The present invention relates to a cyclic sewing device, a method thereof, and a sewing machine having the cyclic sewing device, in which the sewing threads of the needle head set are rotated and towed by a sewing thread traction member consequentially under the reciprocating movement of the needle head set. A sewing thread blocking member blocks and delays the time of connecting the sewing threads to cloth, thereby further achieving the cyclic sewing function. Also, the sewing thread blocking member can be installed corresponding to the large hook unit of the cyclic sewing device in collaboration with the existing sewing machine, and the bottom thread unit can be removed, so that the original top thread can achieve the cyclic sewing function in collaboration with the delay function of the sewing thread blocking member; thus, the functions of the existing sewing machine are more complete.