A video processor that is connectable to an endoscope and an external light source device that supplies illumination light to a light guide of the endoscope includes: a connection detector that detects a presence/absence of connection between the video processor and the light guide of the endoscope an internal light source unit that supplies the illumination light to the light guide of the endoscope a communication controller that performs communication with the external light source device, and obtains device data of the external light source device and a utilized light source determination unit that determines a light source that supplies the illumination light to the light guide of the endoscope in accordance with a detection result of the connection detector or a state of obtainment of the device data of the communication controller.
