A periphery monitoring device for a work machine includes imaging devices that capture an image of the surroundings of the work machine. An overhead view image is generated from the surroundings of the work machine based upon upper view-point images of the image devices. When generating an overhead view image of an overlap region of first and second upper view-point images relating to the images captured by the first and second imaging devices, the overhead view image generating unit, based upon a height of a virtual monitoring target, sets at least one of a first region in which the first upper view-point image is displayed and a second region in which the second upper view-point image is displayed, and also sets a third region in which a composite display image based upon the first and second upper view-point images is displayed.