The invention discloses a self-rescue slow descending device, which comprises a safety rope fixing ring, a safety hook, a safety belt, a load-bearing fireproof rope, a casing, and two rectangular friction plates arranged in the casing, a brake control handle, two semicircular friction sheet, long rod and short rod; the safety rope fixing ring is connected to the upper end of the load-bearing fireproof rope; the safety hook is arranged on the outside of the shell and connected with the safety belt; wherein, the rectangular friction sheet and the semicircular friction sheet are paired with one side high and one side The lower part is fixed on both sides of the inner side of the shell, and the rectangular friction plate and the semicircular friction plate correspond to the load-bearing fireproof rope. The upper semicircular friction plate is connected to the long rod, the lower semicircular friction plate is connected to the short rod, and the long rod is connected to the short rod. Hinged, the spring is installed between the short rod and the long rod and the two ends are respectively arranged on the long rod and the short rod, and the brake control handle is housed on the long rod and the short rod. With such arrangement, the self-rescue slow-descent device disclosed in the present invention can effectively escape by itself, quickly and efficiently.