A suture instrument comprising: a suture tool having an anchor for anchoring to a biological tissue and a suture thread which is adapted to be drawn out of the anchor; a hollow puncture needle which has an opening at the distal end thereof and which is adapted to house the anchor; a pusher which is disposed to advance and retreat in the puncture needle and of which the proximal end extends to a proximal side in a state where the distal end thereof is in contact with the anchor; a second operating portion which is connected to a proximal end of the pusher; an outer sheath which houses the puncture needle, wherein the puncture needle is adapted to advance and retreat therein; an engaging portion detachably engaged with the suture thread and disposed in the puncture needle or in the pusher; an operating portion body which is connected to and extended from a proximal end of the outer sheath; and a first operating portion which is fixed to a proximal end of the puncture needle and is disposed in the operating portion body so as to advance and retreat, the first operating portion having a protruding member and a branch section, wherein the branch section extends in the direction of a center axis which is inclined relative to the center axis of the operating portion body and is connected to the protruding member, the second operating portion is disposed to advance and retreat relative to the first operating portion, the suture thread is adapted to be drawn in a state where the anchor is housed in the puncture needle, the anchor comprises a first anchor and a second anchor, the suture tool comprises a stopper which is disposed on the suture thread, the suture instrument further comprises a resilient member connected to the second operating portion, a movable stopper fixed to the branch section and configured to advance relative to it from a distal positon to a proximal position, and a lock member disposed in the movable stopper and configured to switch the movable stopper between a movable state and a fixed state relative to the first operating portion, wherein the second operating portion is adapted to move the pusher distally relative to the puncture needle and upon the maximum compression of the resilient member move the pusher by a distance corresponding to the length of the first anchor when the stopper is in the fixed state in its proximal position; and the resilient restoring force of the resilient member is set smaller than the frictional force generated over the entire length between the pusher and the puncture needle such that when the movable stopper is switched to the movable state, the resilient member restores to its original length without causing a relative movement between the pusher and the puncture needle and thereby causes the movable stopper to advance relative to the branch section to its distal position. a suture tool having an anchor for anchoring to a biological tissue and a suture thread which is adapted to be drawn out of the anchor; a hollow puncture needle which has an opening at the distal end thereof and which is adapted to house the anchor; a pusher which is disposed to advance and retreat in the puncture needle and of which the proximal end extends to a proximal side in a state where the distal end thereof is in contact with the anchor; a second operating portion which is connected to a proximal end of the pusher; an outer sheath which houses the puncture needle, wherein the puncture needle is adapted to advance and retreat therein; an engaging portion detachably engaged with the suture thread and disposed in the puncture needle or in the pusher; an operating portion body which is connected to and extended from a proximal end of the outer sheath; and a first operating portion which is fixed to a proximal end of the puncture needle and is disposed in the operating portion body so as to advance and retreat, the first operating portion having a protruding member and a branch section, wherein the branch section extends in the direction of a center axis which is inclined relative to the center axis of the operating portion body and is connected to the protruding member, the second operating portion is disposed to advance and retreat relative to the first operating portion, the suture thread is adapted to be drawn in a state where the anchor is housed in the puncture needle, the anchor comprises a first anchor and a second anchor, the suture tool comprises a stopper which is disposed on the suture thread, the suture instrument further comprises a resilient member connected to the second operating portion, a movable stopper fixed to the branch section and configured to advance relative to it from a distal positon to a proximal position, and a lock member disposed in the movable stopper and configured to switch the movable stopper between a movable state and a fixed state relative to the first operating portion, wherein the second operating portion is adapted to move the pusher distally relative to the puncture needle and upon the maximum compression of the resilient member move the pusher by a distance corresponding to the length of the first anchor when the stopper is in the fixed state in its proximal position; and the resilient restoring force of the resilient member is set smaller than the frictional force generated over the entire length between the pusher and the puncture needle such that when the movable stopper is switched to the movable state, the resilient member restores to its original length without causing a relative movement between the pusher and the puncture needle and thereby causes the movable stopper to advance relative to the branch section to its distal position.