An inductively coupled plasma mass spectroscopic includes a sample introduction section for nebulizing a sample solution; an ionization section, including a torch, for ionizing a nebula of a sample solution that is carried with a carrier gas; an interface section for sampling the ionized elements in the nebula at an atmospheric pressure and directing ions of the ionized elements into an ion lens section under a vacuum; the ion lens portion, containing an ion beam guide, for converging the ions which have passed through the interface section wherein at least one part of the ion lens portion is a multipole ion beam guide with at least four electrode rods; a mass selection portion, having a mass filter, for filtering the ions based on the measured mass number; and a detection section for counting filtered ions.