PROBLEM TO BE SOLVED: To improve the reliability of an escalator by monitoring whether or not a step is in a specified attitude in a specified route. SOLUTION: A motor 4 and a brake 5 are connected to a control device 3, and the drive/step of a step of an escalator is controlled by controlling the motor 4 and the brake 5 by the control device 3. A step attitude detection part 1 detects the attitude of the step of the escalator, and outputs the detection signal to a normality/abnormality judgment part 2. The normality/abnormality judgment part 2 judges whether the attitude of the step is normal or abnormal based on the detection signal from the step attitude detection part 1, and informs the result of judgment to the control device 3. When the result of judgment that the attitude of the step is abnormal is received, the control device 3 controls the motor 4 and the brake 5 to stop the escalator.