PROBLEM TO BE SOLVED: To provide a technology capable of separating a plurality of kinds of video signals having different wavelengths of light to be irradiated in accordance with the wavelengths by a simple method even when the video signals are simultaneously acquired.SOLUTION: An image processor 13 extracts a frame image from a video signal, from one video stream in which first and second video signals based on first and second light, respectively, the video signals acquired by alternately irradiating the first and second light having different wavelengths outputted from a light source device 3 to an observation object 5. The frame image is analyzed, and it is determined which the frame image is between the first and second video images by determining which feature is included by the frame image between features respectively belonging to the first and second video signals. A video stream of the first video signal and a video stream of the second video signal are separated from the video stream and outputted on the basis of a detection result of a detection part.
