Abstract: An image signal treatment apparatus prevents degradation of picture quality which can occur because of various interferences phenomena arising from causes such as a hanging dot and its motion. The inventive apparatus performs proper correlation by taking into account the motion components of a composite image signal during Y/C signal separation. The inventive apparatus separates the luminance and chrominance signals of the composite image signal according to the motion components with respect to the composite image signal during separation. The apparatus is provided with filters which output luminance and chrominance signals by filtering the composite image signal horizontally, vertically and temporally. Motion detection circuitry outputs detection coefficients by detecting vertical and horizontal motion of the composite image signal. Mixers are provided to mix the luminance and chrominance signals outputted from the filters according to the detection coefficients of the respective motion detection circuitry.