Pancreatic cancer can be detected by producing a monoclonal antibody which can bind to pancreas specific RNase 1 when no sugar chain is bound to a site located in the pancreas specific RNase 1 and capable of being modified with an N type sugar chain and of which the binding to the pancreas specific RNase 1 is inhibited when an N type sugar chain is bound to the site also producing a monoclonal antibody which can bind to the pancreas specific RNase 1 simultaneously with the binding of the aforementioned antibody to the pancreas specific RNase 1 and determining the ratio of A to B using the antibodies wherein A represents the amount of the site located in the pancreas specific RNase 1 and capable of being modified with an N type sugar chain wherein an N type sugar chain is bound or unbound to the site； and B represents the amount of the site located in the pancreas specific RNase 1 and capable of being modified with an N type sugar chain.
