To provide a lift platform that ensures safety by racing and protecting an electric motor upon an overload, and preventing a reverse rotation of a feed screw mechanism and preventing fall of a lift platform.

A lifting and lowering device 1 comprises the lift platform for bearing a load, a driving electric motor 2 for lifting and lowering the lift platform, a reduction gear mechanism 3, 22, 26, 27, 28 coupled to an output shaft 20 of the electric motor 2, and a feed screw mechanism 5 consisting of a driving screw 6 coupled to the output shaft 28 of the reduction gear mechanism and a moving nut 7, wherein the lift platform is coupled to the moving nut 7 of the feed screw mechanism 5. A limiter 23, 24, 42 is provided to race the electric motor 2 when an overload is applied to the lift platform, and backstop mechanisms 32, 34, 36 is provided to prevent a lowering movement of the lift platform during the racing.