An image signal processing unit includes a frame rate conversion circuit performing double frame rate conversion on an input image signal from a first frame frequency to a second frame frequency. When performing frame rate conversion with the motion correction process, a motion vector is determined between a first frame image and a third frame image, and three interpolation frame images are formed through the motion correction process to the first frame image based on the motion vector, and are inserted between the first and third frame images so as to establish the second frame frequency. When performing frame rate conversion without the motion correction process, an interpolation frame image same as the first frame image is inserted between the first and second frame images, and an interpolation frame image same as the second frame image is inserted between the second and third frame images.