There is provided a gas analyzer apparatus that analyzes inflowing sample gas. The gas analyzer apparatus includes a filter unit that filters the sample gas, a detector unit that detects the result of filtering, a housing that houses these elements, and a control unit that controls the respective potentials of these elements. The control unit includes a cleaning control unit that sets the respective potentials of the filter unit, the detector unit, and the housing to cleaning potentials that draws in, as plasma for cleaning purposes, process plasma from a source that supplies the sample gas or plasma generated by a plasma generation unit.