PURPOSE: To prevent smoke and sparks from flowing in a lift path by providing a hollow expansion smoke interrupting material in a space between a landing door and a gate peripheral edge part, opening a supply control valve, and injecting incombustible fluid into the expansion smoke interrupting material to expand it, when a smoke sensor provided in a landing is operated.

CONSTITUTION: In a space G1 between a landing door 1 and a side edge part 2a (and upper/lower edge parts) of a gate 2 of a landing, a smoke interrupting material 3, consisting of expansible five resistant rubber 3a, is mounted by a holding tool 3c and a bolt 3d on the side edge part 2a over its total length with a predetermined cavity spaced. Closed internal space 3b of this smoke interrupting material 3 is connected to a supply tank through a flow pipe of interposing a supply valve. When smoke is detected by a smoke sensor, provided in the landing, and continued to be detected for a preset time or more, the supply valve is opened to supply incombustible fluid in the supply tank to the internal space 3b of the smoke interrupting material 3, and it is expanded to close the space G1. In this way, smoke and sparks are prevented from intruding into a lift path from the space G1.