To solve a problem that safety insurance of spreading of a natural ignition material including a resin or chemicals caused by suction/dust collection of a heating material dust or based on variety of the material of the processed dust, especially, ignition at an inhabited working place by suction of a firing factor material at the time immediately after completion of work not depending on consciousness or unconsciousness at welding, cutting, grinder flame and other environments of many heat source works of a steel processing in situ is desired from the purpose of acceleration of world-wide human beings health in variety of an industrial field.

Not only a dust collection filter material is made of a flame resisting material or a non-inflammable material as a matter of course, but also thermal sensing is performed and automatic water-spraying or automatic fire-fighting apparatus is provided even at the inhabited working place including fine dusts scattered in a dust collection filter chamber.