A first signal transmission apparatus installed in an operating room and a second signal transmission apparatus installed in a remote control room in a remote place are linked by a public line. Assuming that surgery is performed on a patient using a surgical instrument in the operating room while endoscopic images are viewed, the surgical instrument can be controlled using a first controller. The control and patient data are displayed on a display device via a second controller connected to the second signal transmission apparatus. The state of the surgical instrument and the patient data can always be checked in the remote control room. Surgical instructions or any other surgical support can be given easily.