Gas Analysis Device and Gas Analysis Method

A gas analysis device and a gas analysis method capable of performing measurement in a direct mode and a trap mode without carrying out a complicated control. The gas analysis device includes a branching section that branches a target gas, a mass spectrometer that carries out mass spectrometry of one branched target gases, a trap section that holds the other branched target gases, a gas chromatograph that analyzes the other branched target gas held by the trap section, and a controller that controls the flow path of the one branched target gas and the other branched target gas. The branching section is controlled so that, while the thermal analysis is being carried out by the thermal analysis device, the branching section continuously branches the supplied target gas and discharges one branched target gas and the other branched target gas, and when the thermal analysis has been completed, the other branched target gas held by the trap section is supplied to the gas chromatograph.