A radiation treatment system that can apply radiation to a respiratory moving organ (such as, a lung, a liver or the like) with high precision is provided. A radiation treatment system according to the present invention as solving means is characterized in that when medical treatment target position information obtained by executing pattern matching processing on the inside of each frame of a fluoroscopic X-ray image for detecting a medical treatment target position achieved under medical treatment on the basis of a template image of an area containing a medical treatment target position of a patient, which is achieved in advance, is within a predetermined error range with respect to the medical treatment target position information based on the template image, and also a timing is an application timing of medical treatment radiation which is set on the basis of motion information of a body surface, a signal for applying medical treatment radiation is generated; and in the other cases, a signal for stopping the application is generated, whereby the application of the medical treatment radiation is controlled on the basis of these signals.