The invention discloses a building climbing device with a mechanical lock, and the device comprises bearing box bodies, first gear boxes, second gear boxes, and control cabinets. The first gear boxesare disposed on the bearing box bodies, and climbing motors are disposed on the first gear boxes. Supports are disposed between the bearing box bodies, and reinforcing cross beams and reinforcing inclined beams are disposed between the supports. Support vertical columns and racks are disposed between the supports and the bearing box bodies, and sliding rods and sliding rails are disposed between the support vertical columns and the supports. The beneficial effects are that the device is reasonable in structure, is simple in operation, is convenient to use, is high in climbing speed, and is high in stability; the device can bear articles and completes the quick climbing, improves the construction speed of building engineering, and can be temporarily locked in electric and manual control modes; the device is more convenient and practical, and is higher in safety.