This invention concerns a method and apparatus for vaporization injection of large volumes of liquid sample (substance to be analysed+solvent) introduced by a syringe needle into a heated vaporization chamber which is part of an injector coupled operatively to a device for gas chromatographic analysis. The sample is sent in the form of a liquid band traveling through the vaporization chamber at high speed until it reaches a stopping and vaporization device positioned adjacent to the inlet of a capillary to collect the vapors. In order to inject large volumes without modifying the vaporization chamber and without partial losses of the samples, the sample vapors, in splitless mode, are drawn up from the vaporization chamber into the capillary by virtue of the local action of volume contraction caused by recondensation of at least the solvent vapors in the capillary.