By the way, “fast GC”, one of the GC methods, has become to attract attention recently. The fast GC method can shorten the analysis time remarkably while keeping a good separation ability equal to the conventional GC methods, by using a narrow and short column of about 0.1 mm inside diameter and 10 m long. The fast GC method, adopted in a GC-MS system, has the ability to improve the system throughput. However, it requires a fast spectrum- acquisition speed to the mass spectrometer, because the chromatograph peaks are narrower in time than a conventional GC. TOFMS only has the ability to satisfy the demand for fast spectrum-acquisition speed at the present time, but the existing GC-TOFMS systems are not satisfactory by either of the following reasons: it can follow the fast speed of the fast GC, but its mass resolution is too low to measure accurate mass, or, on the inverse, it has a mass resolution high enough to measure accurate masses but cannot follow the fast speed of the fast GC.