Elevator system

The invention discloses an elevator system which is provided with a lift car accidental movement protecting device. When the elevator lift car starts to goes up or down from a floorslab of an elevator lobby on the condition that a lift car door and a landing door are open, the lift car accidental movement protecting device judges that the lift car moves accidentally and abnormally and stops the lift car. The elevator system comprises a lift car door switch (43) for detecting the open state of the lift car door, a landing door switch (41) for detecting the open state of the landing door, a detecting device (21) for detecting the speed and amount of movement of the lift car, a position sensor (30) for detecting the floor reference position of each floor, and a security controller (1) for judging lift car sudden movement abnormity according to the detecting results of the detecting device (21) and the position sensor (30) and an abnormity judgment threshold value which is set according to the lift car position and used for judging speed abnormity of the lift car. Therefore, the lift car accidental movement is practically detected within a shorter movement distance (as early as possible), and the reduction of the operating efficiency of the elevator is prevented while the security is improved.