A distance image processing device, a distance image processing method and a distance image processing program according to the present invention obtain a distance image having a plurality of pixels corresponding to each of a plurality of directions different from each other based on a plurality of transmitted waves and a plurality of reflected waves and determine a target region as noise if a gradient of a distance value between the target region and a predetermined peripheral with respect to the target region is within a predetermined range and a pulse width of the reflected wave relating to the target region is larger than a pulse width of the reflected wave relating to the peripheral region when a predetermined region in the distance image is the target region. A recording medium records such a distance image processing program.