Provided is a guide display device with which incorrect recognition of a place having small features as a ground surface having no features can be suppressed in generating and updating a three-dimensional map. A data processing unit (70): detects an edge (Eg) of a feature (E) on the basis of a result of subjecting image data captured by a camera (61) to image processing, and recognizes the feature (E) on the basis of the edge (Eg); and accumulates, from a predetermined number of frames from before the time at which the image data was captured, point group data (P) of a nearby range (Ma) of the edge (Eg) of the feature (E) that was recognized as a ground surface (F), and generates, on the basis of the accumulated point group data (P), a three-dimensional map (M) of the feature (E) the edge (Eg) of which has been recognized.