PURPOSE: To eliminate the instability of a footstep due to the fluctuation of the number of persons thereon by keeping the footsteps horizontal and parallel to each other, and achieving the drive by a parallel pin and pin gear mechanism on the Inner side, and by a scratch-chain mechanism on the outer side.

CONSTITUTION: A motor 9X, a reduction gear 9Y, and a large diameter gear 80 fitted to a vertical shaft 820 of a bevel gear 82 to be engaged with a bevel gear 81 on a shaft 91 are driven. While, a bevel gear 83 of the same size as that of the bevel gear 81 is engaged with the bevel gear 82, and rotated in the reverse direction. A shaft 93 is rotated in the reverse direction to that of the shaft 91, and scratch chain sprockets 910, 930 on the descending side and the elevating side are driven by the shaft 91 and the shaft 93 by the chain drive through intermediate sprockets 91a-91d, 93a-92d. The large diameter gear 80 having the vertical shall 820 is engaged with a pin gear 14 provided on the footstep, the corner part on the inner side of the footstep is eliminated to allow the contact without interference with the adjacent footstep, serving for the stabilization of the revolving footsteps.