An endoscope system of the present invention has a video processor and a light source device, and an endoscope can be connected thereto. And a control portion of the light source device detects connection with the endoscope and the video processor, detects connection with the video processor and the light source device and detects the type of the endoscope by an endoscope detection portion. And when non-connection of the endoscope and the video processor is detected, or non-connection of the video processor and the light source device is detected, the control portion controls so that the light amount of illumination light supplied from the light source device to the endoscope becomes a predetermined light amount according the detected type of the endoscope.