The present invention relates to a minimally invasive surgical instrument having an articulation immobilising structure. According to one aspect, the present invention is a minimally invasive surgical instrument comprising: a shaft an end effector connected towards one end of the shaft a wire for controlling the articulated movement of the end effector and an immobilising structure adapted to immobilise the state of articulated movement of the end effector. The immobilising structure comprises a resilient member covering the wire, and the resilient member holds the wire when an internal space therein contracts.
