There is provided a gas analyzer apparatus including: a sample chamber which is equipped with a dielectric wall structure and into which only sample gas to be measured is introduced; a plasma generation mechanism that generates plasma inside the sample chamber, which has been depressurized, using an electric field and/or a magnetic field applied through the dielectric wall structure; and an analyzer unit that analyzes the sample gas via the generated plasma. By doing so, it is possible to provide a gas analyzer apparatus capable of accurately analyzing sample gases, even those including corrosive gas, over a long period of time.