PURPOSE: To jet an extinguishing gas without any reduction in pressure by a method wherein a trigger needle of an upper cover part and a protrusion part are inserted and fitted into a cylinder support part to screw a cylinder support part down on an internal fixed part and a safety plate is inserted to screw the upper cover part down on an outer circumference fixed part and a lower cover.

CONSTITUTION: A head part 4 of a cylinder 1 is made to stick out from an insertion hole 24 of an internal fixed part 23 and the head part 4 sticking out of the cylinder 1 is screwed down into an insertion hole 11 having an O ring 26 of a cylinder support part 9 inserted thereinto to screw the cylinder 1 down on the cylinder support part 9. A protrusion part 19 of an upper cover part 17 is fitted into a vertical through hole 13 of the cylinder support part 9 while an upper cover part 17 is screwed down on the internal fixed part 23. A leg part 15 of a safety plate 14 is inserted into a recess part 16 of the cylinder support part 9 through a hole part 22 of the upper cover part 17. Moreover, the upper cover part 17 is screwed down on an external fixed part 6, a lower cover 8 is screwed down on the external fixed part 6 and a bottom part 5 of the cylinder 1 is made to stick out from a lower opening part 8' of the lower cover 8 to assemble.