Abstract: A suturing instrument for use in surgical operation to suture up a wound or the cut out flesh with lock stitches substantially comprises a support, a needle bar secured to the support, a curved needle removably attached to one end of the needle bar and supplied with a needle thread, a holder bar mounted on the support and axially movable relative to the support to and away from a thread loop formed at the curved needle during the suturing operation, a shuttle holder mounted on one end of the holder bar, a shuttle removably mounted in a space defined by the shuttle holder and supplied with a shuttle thread, pawl means for detaining the shuttle in the space of the shuttle holder, said shuttle being of a streamlined structure pointed at the forward end thereof and having a rear end, said shuttle being positioned in the space of the shuttle holder in a manner that the pointed forward end thereof is directed to the support and the rear end thereof is directed to the curved needle, so that the shuttle may traverse