A gas analyzing apparatus includes: an ionization device that generates an ion flow of a sample gas; an analyzer that analyzes the ion flow supplied from the ionization device; a first ion path that non-linearly guides the ion flow from the ionization device to an inlet of the analyzer; and a blocking device for intermittently blocking and releasing, using an electric field or a magnetic field, the ion flow on at least part of a path of the ion flow through the first ion path to a mass filter of the analyzer. It is possible to perform measurement in a state where the ion flow is blocked and measurement in a state where the ion flow is not blocked.