PURPOSE: To eliminate mounting of a switch actuating piece, allow automatic determination even though the brake distance is not measured by any scale, and displaying precisely by calculating and displaying the brake distance when a man conveyor is stopped on the basis of signals generated according to the movement of handrails.

CONSTITUTION: When the brake distance is to be measured at the time of maintenance or inspection, pulse signals are emitted from an encoder 15 until handrails 11 stop, and the brake distance is displayed on a display 23 upon adding. or subtracting in the case of reverse rotation. Pulses fed anew are added to the previous indication in the case of regular rotation and subtracted from the same in the case of reverse rotation. While the man conveyor is moving, on the other hand, the display device 16 remains reset as it has been. If the conveyor is started and stopped, therefore, the slip amount is indicated directly on the display 23, so that no switch actuating piece is required, and measurement can be done accurately.