A method of confirming a certificate by using a management computer that issues the certificate is disclosed. The management computer is coupled to an application terminal for applying for issuance of the certificate and to a confirmation terminal for reading a display code printed on the certificate. The management computer performs the steps of: specifying contents to be certified based on an application item received from the application terminal; issuing the certificate by calculating a compressed value by substituting data related to the contents to be certified into a one-way function, and by generating print data for printing a display code including the compressed value and the contents to be certified; recording an issuance history of the certificate; and when data of a compressed value are received from the confirmation terminal that reads the display code on the certificate, notifying the confirmation terminal of authenticity of the certificate based on a result of comparison between the received compressed value and the compressed value calculated in the step of issuing the certificate.