1. A video signal selector comprising: a selector switch for selecting one of a first output mode and a second output mode, for outputting an endoscopic video signal as an output video signal in said first output mode, and outputting another medical video signal as said output video signal in said second output mode, said endoscopic video signal and said medical video signal being inputted in parallel with one another to said selector switch; and a selector control circuit for controlling said selector switch so as to switch from said first output mode to said second output mode in response to a first image capture command for capturing an image from said medical video signal, wherein said selector control circuit further controls said selector switch so as to switch from said second output mode to said first output mode in response to a second image capture command, wherein said video signal selector has an input side and an output side, to said input side an endoscopic video signal processor for producing said endoscopic video signal and a medical video signal processor for producing said medical video signal are connected, to said output side an image server for storing an image is connected, and said image server captures said image from said output video signal selected by said selector switch in response to said first image capture command or said second image capture command, wherein said selector control circuit controls said selector switch so as to switch from said second output mode to said first output mode, when said image server has completed saving said image captured from said medical video signal, and wherein said selector control circuit refuses acceptance of said second image capture command, while said selector switch is in said second output mode.