A gas injector which can inject at a uniform velocity and an injector pipe used for the same. The gas injector includes a body, a gas flow path formed inside the body, the gas flow path extending from one end to the other end in a lengthwise direction of the body, a blade formed inside the body and connected to the gas flow path so as to inject gas, and an injector pipe inserted into the gas flow path. The injector pipe receives the gas from the gas supply, and distributes the gas through a plurality of holes to the gas flow path. The plurality of holes of the injector pipe include a plurality of first holes and a plurality of second holes which are formed along two parallel lines extending in the lengthwise direction of the injector pipe, the first holes alternating with the second holes.