Abstract: An image signal processing device 1 comprises a delay part 10, a motion detection part 20, an intermediate frame generation part 30 and an output part 40. The motion detection part 20 detects a motion of an image of a second frame with respect to an image of a first frame based on image data G1 of the first frame to be output from the delay part 20 and image data G2 of the second frame to be input to the delay part 20. The intermediate frame generation part 30 generates image data GC of an intermediate frame based on the image data G1 and G2 of the first frame and the second frame, respectively. An edge in the image of the intermediate frame is located between edges in the images of the first frame and the second frame, respectively. The output part 40 inserts the image data GC of the intermediate frame before the image data G2 of the second frame and outputs the data.