This periphery monitoring device for a crawler-type working machine comprises: cameras (61)-(64) that capture images of the periphery; a display means (65) that displays the images captured by the cameras (61)-(64); and a control means (66) that superimposes outer edge reference images on the display means (65), the outer edge reference images being formed on the basis of the position of a lower traveling body that is farthest from the rotational center of the crawler-type working machine.