The invention relates to a safety brake for an elevator, a centrifugal regulator and a way of using this in a safety brake. According to the invention, the safety brake comprises a centrifugal regulator (3), a shaft (4), which rotates due to a coupling (5) to the elevator, a first (6) and a second (8) brake part movable against each other with friction surfaces (10, 11), the first brake part being rotatable with the shaft, a spring assembly (30) with which the brake parts are spring-biased with a pressure force, on release the centrifugal regulator is provided to couple the shaft (4) to the first brake part (6) to force rotation on it. The safety brake is self-regulating by comprising the pressure-relieving arrangement provided, due to the rotation of the shaft (4), to relieve the spring biasing by pressing the first brake part (6) towards the spring assembly's (30) spring action and thus from the other brake part (8), until a balanced position is obtained whereby both brake parts (6, 8) frictionally slide against each other.