The purpose of the present invention is to more reliably prevent a runner coming off a rail when an immobilizing band is in use. This subject immobilizing device comprises: a rail which is attached to an immobilizing platform and a runner which is combined with the rail so as to be slidable along the longitudinal direction of the rail, and whereto is connected an immobilizing band for immobilizing a subject to the immobilizing platform. The runner comprises: a runner main body which is housed in the inner side of the rail and a band connection part which protrudes externally from the rail and whereto the immobilizing band is connected. The rail comprises: a rail main body which slidably retains the runner main body and first and second attachment parts which protrude externally from the rail main body and which are attached to the immobilizing platform, being positioned so as to clamp an end part of the immobilizing platform. A slit is disposed upon the rail main body along the longitudinal direction thereof, said slit preventing the runner main body from passing therethrough while allowing the band connection part to pass therethrough.La présente invention a pour objet dempêcher de manière plus fiable le déraillement dun coulisseau lorsquune bande dimmobilisation est en utilisation. Ce dispositif dimmobilisation dun sujet comprend: un rail fixé à une plate-forme dimmobilisation et un coulisseau combiné au rail de manière à coulisser dans le sens longitudinal du rail, et auquel est fixée une bande dimmobilisation servant à immobiliser un sujet à la plateforme dimmobilisation. Le coulisseau comprend: un corps principal de coulisseau logé dans le côté intérieur du rail et une pièce de fixation de bande faisant saillie vers lextérieur à partir du rail et à laquelle la bande dimmobilisation est fixée. Le rail comprend: un corps principal de rail qui retient en coulissement le corps principal de coulisseau et des première et seconde pièces de fixation qui font saillie ve
