A fall arrester includes holder, rotating drum, and braking module. The rotating drum is pivotally installed on the holder, and includes main body and pawl which has first abutting portion and is pivotally provided on setting part. The braking module is fixed to holder, and includes cover, friction plate, and ratchet plate, being coaxially set in order. The ratchet plate has second abutting portion on its periphery. When rotating drum rotates at speed greater than or equal to predetermined rotating speed, and first abutting portion moves to second position to abut against second abutting portion, the cover and ratchet plate rotate relative to friction plate, driven by rotating drum. Additionally, the cover and ratchet plate generate frictional resistance with friction plate respectively to stop the rotating drum. Thus, the braking module of the fall arrester can be replaced thereby enabling provision of a new braking module as an initial condition.