To provide a video signal processing circuit and a video processing method, capable of improving image quality by simple constitution.

A motion detection circuit 102 detects the presence of the motion of video images, based on composite video signals VD, and the output signals of a frame memory 101 and a three-dimensional Y/C separation circuit 103 separates luminance signals Y1 and chrominance signals C1 from the composite video signals VD, based on motion signals MS1 outputted from the motion detection circuit 102. A motion detection circuit 107 detects the presence of the motion of the video images, based on the luminance signals Y1 outputted from the three-dimensional Y/C separation circuit and a combining circuit 108 combines the motion signals MS1 and MS2 outputted from the motion detection circuit 102 and the motion detection circuit 107. A three-dimensional noise reduction circuit 106 reduces the noise of the luminance signals Y1, which is outputted from the three-dimensional Y/C separation circuit 103, based on the output signals of the combining circuit 108.