A mountainous or valley-shaped curved part 13 is provided in a part of a footstep guide rail 3 for guiding a movement of footstep rollers 5 linked by a footstep chain 7, the part being positioned in the vicinity of a drive sprocket 9. Consequently, owing to meshing of the footstep rollers 5 with the drive sprocket 9, an unevenness in velocity of the footstep rollers 5 is absorbed by the curved part 13, so that a moving velocity of the footstep rollers 5 moving on the downstream of the curved part 13 is maintained constantly, suppressing vibrating of the footsteps 4.