This invention relates to an analytical method and an apparatus therefor utilizing a solid phase cartridge, which can realize enhanced accuracy and workability in the analysis of trace substances, such as residual pesticide, demanded with an ever-increasing importance of environmental problems and, at the same time, can clean the inside of piping, needle valves and the like, can eliminate the influence on the analysis and can conduct these operations automatically. In the analytical method and apparatus therefor utilizing a solid phase cartridge, an analyte previously adsorbed to a solid phase cartridge is eluted with a solvent from a liquid feed pump. The eluate was injected into a storage chamber in a gas chromatograph through a needle inserted into an injection port in the storage chamber. The needle is then pulled up from the injection port, and the inside of the needle is washed with a solvent fed from the liquid feed pump. The wash liquid is discarded, and the analysis of organic chemical substances as an analyte in an analyte sample is continuously carried out.