A storage box 100, on the bottom surface of which are attached casters 101, has a heater 102 positioned on the bottom surface thereof and left-hand side and the right-hand side interior spaces being divided by a partition plate 103, wherein nine (9) sampling bags 104 . . . in total can be received within a wide space at the right-hand side thereof. On one side of the storage box 100 is provided a connector unit 110. This connector unit 110 is constructed with an elevating block 112 hooking on guide rails provided in a direction of up and down, and the elevating block 112 is biased upward with a gas spring 113. In guide holders 112b of the elevating block 112 are provided guides 115 . . . in the same number as the number of the sampling bags 104, and into each guide 115 is inserted a flexible conduit 116 made from stainless steel, in a such manner that it can be drawn out therefrom. Heaters and warm air passages are provided to prevent the condensation of moisture within a sampled gas under a range of operating conditions.