In a color image display system formed of a monochromatic CRT or like image display device (102) having a screen (103) for display of images and a rotary filter (106) comprising color filter sections (106R, 106G and 106B) of a plurality of colors; image signals are read from memories (130R, 130G, 130B) at a rate higher than they are written in the memories, so as to reduce flickers. The problem of passing of the reading address over the writing address is solved by reading the image signal of prominent color taking a period in which the passing over occurs. High frequency components of other color image signals are extracted and added to the image signal of each color to thereby enhance the definition of the picture.