An image search apparatus includes a hard disk. A plurality of images photographed by a surveillance camera are recorded on the hard disk with luminance information. When an arbitrary image is selected as a reference image from among the plurality of images recorded on the hard disk, and an arbitrary area of the reference image is designated as a search area, a CPU calculates a difference value of the luminance information of the search area between the reference image and each of other images. Furthermore, the CPU specifies an image in which the calculated difference value exceeds a threshold value from among the other images, and the specified image is displayed on the display.