The present invention provides a method for examining colorectal cancer and colorectal adenoma, which enables to detect colorectal cancer patients and patients at high risk of colorectal cancer at a high probability and is useful for diagnosis of colorectal cancer and colorectal adenoma, and provides the examination reagents thereof. The present inventors discovered that there are significant differences in the distribution of GlcNAc-6-sulfotransferase isozymes, sulfation enzymes of sugar residues, among non-cancer colorectal tissues, colorectal cancer tissues and colorectal adenoma tissues. Furthermore the inventors applied the discovery to diagnosis and found that colorectal cancers and adenomas are detected specifically by assaying a definite range of GlcNAc-6-sulfated sugar residues in tissues from patients or feces samples. MECA-79 antibody (Pharmingen, catalog No. 09961D, Distributor: Becton Dickinson), reacting with GlcNAc-6-sulfated sugar residues, which are produced specifically by the enzyme present in colorectal cancer and colorectal adenoma tissues could be used for the examination of colorectal cancers and colorectal adenomas.