PURPOSE: To display two different systems of video signals simultaneously by providing input terminals for a video signal of an existing television system and a High Vision signal, generating a video signal for a slave screen resulting from thinning both the signals and providing a changeover switch for the master screen and the slave screen.

CONSTITUTION: In the case of displaying a High Vision signal onto a master screen and displaying an existing television system onto the slave screen, selector switches 12, 13, 27, 43 are thrown to the position A and the deflection is implemented based on a synchronizing signal of the High Vision signal. Moreover, the video signal for the slave screen is thinned out so that the aspect ratio is 3:4, which offers a natural feeling picture. In this case, a high frequency component is interrupted through a spatial frequency filter 6 so that the deterioration in the picture quality due to loopback is not caused. On the other hand, in the case of displaying an existing TV signal onto the master screen and displaying the High Vision signal onto the slave screen, the selector switches 12, 13, 27, 43 are thrown to the position B and the deflection is implemented based on a synchronizing signal of the existing TV signal.