The present invention relates to a method for analyzing a metalloprotein in a biological sample capable of continuously maintaining conditions of LC-ICPMS constant to measure a metalloprotein with high data reliability. The method for analyzing a metalloprotein which is a complex in a biological sample, the metalloprotein being a complex in which a biomolecule and a metal element bind to each other, includes: treating a biological sample which has been subjected to a pretreatment by liquid chromatography to separate the metalloprotein, and analyzing the separated metalloprotein by inductively coupled plasma mass spectrometry, wherein an ammonium acetate solution is used as a mobile phase.