The present invention relates to an endoscope system including: a real time clock; an interface for receiving medical information output from a peripheral device; and a control unit that adjusts clock information added to the received medical information into clock information of the real time clock when the peripheral device adds the clock information to the medical information, and adds clock information of the real time clock at a time of receiving to the received medical information when the peripheral device does not add the clock information to the medical information. According to the invention, even the medical information obtained from the different devices can be reproduced with data from the respective devices synchronized by associating the clock information based on the identical real time clock therewith. Consequently, even after the surgical operation, the contents of treatment performed during the surgical operation can be accurately reproduced.