An image signal captured by a camera head and outputted from an image processor is inputted into a foot switch control device. The image signal is processed in a display control unit of the foot switch control device, inputted into a display and displayed thereon. The display control unit reads out an image indicating the foot switch state corresponding to the foot switch function that is presently allocated to the inputted endoscopic image from a memory unit and superimposes this image on the endoscopic image.