The retractable fall arrester in accordance with norm EN–360 secures a worker from falling down when carrying out works which require often changing position of their working station, e.g.: assembling and maintenance of bridges, pylons and outriggers, assembling and disassembling of scaffoldings, in mine shafts, in shipyard and building constructions industry. Steel rope is kept taut by the reel, but enables the operator to move freely all over the construction site within the limits of its length. The inertial ratchet mechanism guarantees successful preventing from falling down. The device is excellent for using in the working environment with high level of dust and oil pollution.