An orthogonal type gas laser oscillator is constructed in such a manner that a laser medium gas is caused to flow through an exciting region for the laser oscillation to perform the laser oscillation on the optical axis which runs in the direction orthogonal to the flowing direction of the laser medium gas; the exciting region is provided independently in even number and the flowing direction of the laser medium gas in one half of the exciting region and the flowing direction of the laser medium gas in the remaining half of the exciting region are mutually opposed.
