An object of the present invention is to efficiently extract proteoglycan from aquatic animal tissues. The method of the present invention is a method for extracting proteoglycan from fish cartilage, comprising the step of (A) heating small pieces of frozen fish cartilage in water. This method of the present invention enables easy extraction of proteoglycan from fish cartilage with very high efficiency. In particular, the method of the present invention enables extraction of high-molecular-weight proteoglycan. Further, since in the method of the present invention, extraction is performed using only water, it ensures safety in the extraction and safety of the resulting proteoglycan product, compared with hitherto known extraction methods using organic solvents or acids/alkali. Furthermore, the cumbersome step of removing organic solvents is not necessary in the method of the present invention.
