An image display apparatus capable of adjusting a display picture by an input unit through a computer body is disclosed. When the user inputs a control instruction for adjusting the display picture of the display unit by the input unit connected to the computer body, a control signal addition circuit prepares a control signal Sc corresponding to the control instruction and adds the control signal to a video signal R, G or B or a synchronizing signal Hs or Vs produced by a display control circuit during a vertical retrace period. A control signal separation circuit separates the added control signal Sc from the video signal R, G or B or the synchronizing signal Hs or Vs produced by the control signal addition circuit. A display control circuit produces adjustment signals Sa and Sb on the basis of the control signal from the control signal separation circuit to adjust a video circuit and a deflection circuit. Thus, the user can adjust the display picture by the input unit near at hand without extending the hands to adjustment switches of the display unit.