There is provided a signal processing apparatus comprises an edge amount detection portion for generating a data string of luminance differences of a pair of pixels adjacent to each other or adjacent over some pixels in predetermined number of frames of a luminance signal, detecting a maximum luminance difference from the data string and storing the same; and a correction amount conversion portion for converting the data string of the luminance difference to a contour correction amount based on the maximum luminance value: wherein a correction signal generation portion generates a contour correction signal while changing a gain in accordance with the contour correction amount and outputs the same to a contour correction portion; and the contour correction portion adds the contour correction signal to an image signal by synchronizing, corrects a contour of the image and output the same.