A gas spraying apparatus according to the embodiment of the present invention includes a spray part disposed and aligned on one side outside a substrate in the width direction of the substrate, and having a plurality of nozzles for spraying gas toward the substrate, and a spray control unit for automatically controlling whether or not each of a plurality of nozzles sprays gas such that a gas density distribution type in the width direction of the substrate becomes a targeted gas density distribution type by the gas sprayed through the plurality of nozzles. Therefore, according to the embodiment of the present invention, it is easy to carry out the process with a plurality of types of process types or a plurality of types of gas density distribution types, and a time for adjusting the open or close operation of the plurality of nozzles can be shortened.