A microwave powered gas laser apparatus contains a gas medium (29), and a device (11,12) for exciting the gas medium (29) to a high energy state by a plurality of microwaves. Directions of vibrations of electric fields of the microwaves are different from each other. There may be provided a device for making the microwaves into standing waves respectively, and a device for exposing the gas medium (29) to antinodes of electric fields of the standing waves. <IMAGE>
