PURPOSE: To enable highly sensitive analysis of impurities existing evenly in a wide range on the surface of a solid, by a method wherein a solid surface as sample is melted to gasify and then, the gas obtained is converted to a plasma to perform a mass spectrometry of the plasma generated.

CONSTITUTION: For example, a solid surface of an Si wafer 12 as sample is irradiated with light from an infrared lamp 9, for instance, to gasify by being melted. Then, the gas is converted into a plasma with an induction coupling type torch for plasma emission analysis, for example, an ICP torch 7. Subsequently, the plasma is introduced, for example, to a mass spectrograph 8 to analyze impurities by mass spectrometry. Even when the impurities exist evenly and in a wide range on the solid surface, a mass spectrometry can be performed with a high sensitivity. Thus, heating with the lamp eliminates contamination caused by a heater as noted in a resistance heating or the like thereby making it effective for analysis of a very shallow surface of a solid, namely a superfine quantity analysis.