To provide a medical data preserving method for easily executing management or retrieval when centrally preserving medical data related with medical images or examination results owned by a plurality of medical facilities in a data center without complicating the hierarchical structure of the medical data.

This medica data preserving method comprises a step to prepare third identification information by connecting patient information and medical facility identification information corresponding to medical data acquired by photographing or examination as the purpose of diagnosis for preserving the medical data in a client terminal 13, a step to transmit the medical data and at least the third identification information from the client terminal to a database server 25 and a step to record the received medical data and at least the third identification information by associating them with each other in a recording medium 25 in a database server.