PURPOSE: To increase the video quality, by automatically controlling the focus voltage for the profile in which the lightness of picture is finely changed and for the uniform light part.

CONSTITUTION: A delay line 21 constituting a profile detection circuit 14 is split into two, delay line 21a, 21b serially, and the middle point of connection is connected to a video signal amplifying circuit 12. The output of subtractor 22 is inputted to a full wave rectifying circuit 20 of a focus control circuit 15. A switching circuit 32 selects either one of focus voltages VF1, VF2 according to the output of a threshold circuit 31 and it is applied to a focus electrode of a picture tube 13. Thus, the normal focus voltage VF1 is applied to the profile of a video signal and the focus is shifted to the part having uniform illumination, allowing to reduce the effect of noise on visuality.