PURPOSE: To lighten the stress generated at a supporting place in the thermal extension and contraction of a monorail for the high temperature environment, and secure safety.

CONSTITUTION: A slidable supporting means 10 is arranged as a monorail arranged along the horizontal direction on a supporting wall 4 for dividing the high temperature environment, in an interposed state between the supporting wall 4 and a rail member 1, and the slidable supporting means 10 is equipped with a slidable engagement plate 11 which is installed either on the supporting wall 4 or the rail member 1, and is arranged nearly along the orthogonal direction in the longitudinal direction of the rail member 1, and a shiftable bracket 12 which is engaged in a shiftable manner on the slidable engagement plate 11 and is installed either on the supporting wall 4 or the rail member 11, as the other.