PURPOSE: To enable ultrahigh sensitivity analysis without requiring a clean room or a clean laboratory by adjusting a measuring soln. using two glove boxes.

CONSTITUTION: The lid 10 of a glove box 2 for preparation is opened to put a sample, a standard sample raw soln., a graduated flask and a pipette in the box 2 and air in a room is allowed to flow downwardly to set the clean degree in the box to a class of 100 or less and, thereafter, the hand is introduced into a glove part 11 to prepare a standard soln. for the dilution of a measuring soln. and a calibration curve and this measuring soln. is transferred to a measuring soln. supplying glove box 3 and sucked by the sample introducing fine tube 7 opened to the box 3 to be introduced into the IPC torch part of ICP-MS and ionized to perform quantitative analysis. That is, only by preparing two glove boxes having small volume of about 100-200l, analysis can be performed while the clean degree equal to that of a clean room or a clean laboratory is held and accurate analysis of a ppt order is enabled.