Abstract: An apparatus of changing a display size and a method thereof in an image recording and reproducing apparatus are provided. The apparatus includes an MPEG decoder for separating a signal reproduced by an optical disc reproducing device and outputting the separated signal; a scaler for changing the size of the signal output from the MPEG decoder and outputting the signal having the changed size; and a control unit for controlling to display a screen-size selection screen on the display device, driving the scaler to change the reproduced image to have a selected screen size, and controlling to display the changed image on the display device, thereby changing the display size. Thus, the screen size can be adjusted when the image quality is significantly deteriorated on a large-sized screen, thereby solving a problem of image spread or pixel damage.