PURPOSE: To reduce the space of turnover parts by connecting first and second footboards alternately to shafts of connecting points on the outer peripheral side of a flexible linkage device, extending the second footboards outside the first footboards in the intermediate part of conveying travel, and accommodating the second footboards in the first footboards near the turnover parts.

CONSTITUTION: When low-speed linear parts 4c, 4d of a flexible linkage device 9 travel, the angle formed by an inside link 9a and an outside link 9b is small, and second footboards 10B are pushed by shafts 6 to be accommodated in first footboards 10A. As a result, only the footboards 10A are arranged side by side. Next, when high-speed linear parts 4a, 4b travel, the angle formed by the link 9a and the link 9b is large, the footboards 10B are pushed by the shafts 6 to be extended outside the footboards 10A. The gaps between the footboards 10A are clogged by the footboards 10B to secure the safety of passengers. When turnover parts 4g, 4h travel, the angle formed by the links 9a and 9b is small, and the footboards 10B are accommodated in the footboards 10A. Thus, since the footboards 10B do not project outside, there is no need for large space outside the turnover parts 4g, 4h.