Stereotactic radio therapy (SRT) using a linear Accelerator (Linac) requires high precision in the table position and the center of irradiation. QC procedure is necessary To guarantee high precision of each SRT. As the QC procedure, we use the film shot method, in which the table correction width is derived from target images taken at various gantry angles and table angles. However, QC procedure is so complex that long time is wasted for this procedure. In addition, the degree of precision of QC procedure depends on each technologist. We developed a QC program support system to support QC procedure. This system processes images taken by the film shot method, and outputs the table correction width to adjust target position. For evaluation of our developed system, we compared correction width of obtained from our system with that from, conventional manual operation. Results showed that high degree of precision was achieved by employing our system. By using our system, one double check scheme, QC procedure by using both manual operation and our system, will be realized without any additional time for the procedure.