To provide an autoanalyzer for analyzing a sugar chain contained in a biological sample, in particular, serum. Namely, it is intended to provide a method of analyzing a sugar chain in a sample, which comprises the following steps: A) the sugar chain-releasing step of releasing the sugar chain in the sample; B) the detection sample-preparing step of preparing the released sugar chain for detection; and, in the case of conducting mass spectrometry using a plate, C) the step of forming a plate for the mass spectrometry having the captured sugar chain dotted thereon which comprises the step of providing the tagged sugar chain sample solution obtained in the step B) on a collection plate; and, if required, the step of conducting an operation in a solid phase support-enclosed plate to form the plate for mass spectrometry; and D) the step of analyzing the sugar chain to be assayed.