PURPOSE: To ensure a gap between the curved part of the entrance floor of a curved man conveyor and a joint to an adequate value regardless of superiority or inferiority of the curve accuracy of a supporting member.

CONSTITUTION: A supporting member 9 having nearly L-like configuration in cross section and located directly below the side part of a landing plate 32 is deposited to a truss 2 at the riding on and off deck of the main frame of a spiral escalator. A joint 5 forming a gap 11 between the joint and a side part providing the curve of the landing plate 32 is screwed to the supporting member 9. And, a liner 12 for adjusting the gap 11 between the landing plate 32 side part and the joint 5 to 0.5 to 1mm is held between the supporting member 9 and the joint 5.