Pancreatic cancer can be detected by producing a monoclonal antibody which can bind to pancreatic RNase 1 when no glycan chain is linked to a site located in the pancreatic RNase 1 and capable of being modified with an N-glycan chain and of which the binding to the pancreatic RNase 1 is inhibited when an N-glycan chain is linked to the site, also producing a monoclonal antibody which can bind to the pancreatic RNase 1 simultaneously with the binding of the aforementioned antibody to the pancreatic RNase 1, and determining the ratio of A to B using the antibodies, wherein A represents the amount of the site located in the pancreatic RNase 1 and capable of being modified with an N-glycan chain wherein an N-glycan chain is linked or not linked to the site； and B represents the amount of the site located in the pancreatic RNase 1 and capable of being modified with an N-glycan chain.
