To perform measurement so that a cancer can be detected in an early stage by bringing the blood of a patient into contact with an antigen to the cancer immobilized on an insoluble carrier and inducing the production of an enzyme or cytokine.

When the blood of a patient is brought into contact with an antigen to a cancer immobilized on an insoluble carrier, white blood cells, such as sensitized lymphocytes, etc., which are contained in the blood of the patient and specifically react to the antigen bond to the antigen and the while blood cells are activated and differentiated, resulting in the release of an enzyme or cytokine. The enzyme or cytokine is also released from another immunocyte activated by the reaction. When the patient is suffering from a cancer, the cancer can be detected by measuring the amount of released enzyme or cytokine, because the amount of the released enzyme or cytokine increases. In addition, the bodily burden of the patient can be reduced, because the cancer can be detected from a small amount of blood.