PURPOSE: To improve measurement efficiency by pressing the sample to be measured into a heat chamber from a set position and heating it at a proper temperature, sending its vapor to a measuring instrument main body, and returning it to its original position after measurement.

CONSTITUTION: Sample containers 8 wherein samples 4 are stored are arranged on a turntable 17 circularly around its rotary shaft 24. Then the turntable 17 is rotated slowly and control valves V5 and V7 and a solenoid valve V2 are opened to supply a N2 carrier gas for removing moisture from an A line N1 container 15. Then the atmosphere of the measuring instrument main body 1 is stabilized in a nearly no-water state. Then a solenoid valve V2 is opened to supply the carrier gas to a B line. The solenoid valve is also opened during this period and water is removed from a D line and the solenoid valve V1. An electric motor M3 is driven to drive the lid removing arm 20 of a sample container 8 and remove the lid 16, and the sample container 8 is pressed in the heat chamber 3 by the electric motor M2. The water in the heat chamber 3, sample 4, and container 8 is removed with the carrier gas of the B line. The vaporized moisture is sent to the measuring chamber of the measuring main body through the D line.