A medical suturing instrument comprises: a loop introduction needle a suture thread introduction needle into which suture thread is inserted a housing for holding the loop introduction needle and the suture thread introduction needle substantially parallel a prescribed distance apart a loop forming part which has a loop formed at the tip end thereof and is movably housed inside the loop introduction needle a loop feed/return mechanism provided inside the housing for moving the loop forming part in the axial direction a suture thread feed mechanism provided inside the housing for feeding out the suture thread on the tip end side and a thread housing part provided in the housing for accommodating the suture thread which is supplied to the suture thread feed mechanism.
