A video signal processing device includes: a video signal dividing unit configured to divide a video signal into first to k-th (k is an integer of 2 or greater) partial video signals for each frame; a video change detection unit configured to determine, for each of the first to k-th partial video signals, whether or not a video based on the partial video signals has changed between respective frames, and generate first to k-th video change detection signals representing the respective detection results; and a video sameness determination unit configured to generate a video sameness signal indicating that the video signal has not changed, if the number of video change detection signals that indicate the video has not changed, among the first to k-th video change detection signals, is greater than a prescribed number.