An image mixing circuit usable in a video camera for mixing images with a continuous gradation characteristic in both the luminance signal and color signal is provided. A color separation circuit (3) separates plural image signals into plural luminance signal components and plural color signal components. A control signal generation circuit (4) then generates the control signal needed for image synthesis from the plural image signals. A luminance signal mixing circuit (5) and a color signal mixing circuit (6) then separately mix the respective luminance signal components and color signal components according to the control signal. <IMAGE>
