The present invention relates to a gas sample injection apparatus for gas chromatography analysis comprising: a gas collecting tube for collecting the gas inside a cell and regulating it with an open/close valve to discharge a portion of the collected gas as a gas sample; a gas sampling loop for collecting the gas sample injected into a gas chromatograph; a first switching valve for regulating an injection of the gas sample filled in the gas sampling loop into the column of the chromatography with a carrier gas; a second switching valve connected to the gas collection tube and for regulating a diffusion of the gas sample into the gas sampling loop; and a vacuum pump for vacuum-depressurizing the gas sampling loop, and an injection method using the same.