An emergency escape device, comprising: an escape hole cap fitted to an escape hole P formed in a floor of a fire evacuation area of a building; a guide unit vertically installed below the escape hole cap; a descending unit slidably attached to the guide unit in such a manner as to descend along the guide unit when an evacuee gets on the descending unit; a slowing unit configured to ensure that the descending unit descends along the guide unit at a reduced speed; a returning unit for returning the descending unit descended along the guide unit to an original position where the descending unit is in contact with the escape hole cap; and a locking unit for keeping the descending unit against downward movement in an upper portion of the guide unit, characterised in that the returning unit includes a spiral spring configured to be tightened as the descending unit descends and to be loosened to cause the descending unit to move upward, in that the slowing unit includes: a module box; a driving shaft arranged within the module box; a large gear installed within the module box and fixed to the driving shaft; a small gear installed within the module box and driven by the large gear, the small gear provided with a speed reducing wheel; a plurality of speed reducing pieces radially arranged in the speed reducing wheel to receive centrifugal forces; a speed reducing cover fixed to the module box and arranged to surround the speed reducing wheel and the speed reducing pieces; a pulley fixed to the driving shaft to rotate together with the driving shaft; and a chain wound around the pulley, the chain having a first end portion drawn out from a lower portion of the module box and fixed to the descending unit and a second end portion fixed to the pulley and and in that the returning unit further includes a driving gear fixed to one end of the driving shaft and a driven gear meshing with the driving gear and having a rotating shaft, the spiral spring connected to the driven gear, the spiral spring configured to be tightened as the driven gear rotates in a first direction or to be loosened to cause the driven gear 251 to be rotated in a second direction. an escape hole cap fitted to an escape hole P formed in a floor of a fire evacuation area of a building; a guide unit vertically installed below the escape hole cap; a descending unit slidably attached to the guide unit in such a manner as to descend along the guide unit when an evacuee gets on the descending unit; a slowing unit configured to ensure that the descending unit descends along the guide unit at a reduced speed; a returning unit for returning the descending unit descended along the guide unit to an original position where the descending unit is in contact with the escape hole cap; and a locking unit for keeping the descending unit against downward movement in an upper portion of the guide unit, characterised in that the returning unit includes a spiral spring configured to be tightened as the descending unit descends and to be loosened to cause the descending unit to move upward, in that the slowing unit includes: a module box; a driving shaft arranged within the module box; a large gear installed within the module box and fixed to the driving shaft; a small gear installed within the module box and driven by the large gear, the small gear provided with a speed reducing wheel; a plurality of speed reducing pieces radially arranged in the speed reducing wheel to receive centrifugal forces; a speed reducing cover fixed to the module box and arranged to surround the speed reducing wheel and the speed reducing pieces; a pulley fixed to the driving shaft to rotate together with the driving shaft; and a chain wound around the pulley, the chain having a first end portion drawn out from a lower portion of the module box and fixed to the descending unit and a second end portion fixed to the pulley and and in that the returning unit further includes a driving gear fixed to one end of the driving shaft and a driven gear meshing with the driving gear and having a rotating shaft, the spiral spring connected to the driven gear, the spiral spring configured to be tightened as the driven gear rotates in a first direction or to be loosened to cause the driven gear 251 to be rotated in a second direction.