In a data retrieval/distribution apparatus which retrieves designated information from the collected data in accordance with a retrieval/distribution request sent from a data retrieval/distribution client, and sends a retrieval result to the data retrieval/distribution client, the data retrieval/distribution client sends, to the data retrieval/distribution server, the retrieval/distribution request including a first retrieval condition using a virtual data conversion definition, which is a virtualization of data conversion definitions as a definition for converting the collected data into a distribution format, a processing unit of the data retrieval/distribution apparatus generates a second retrieval condition using each of the data conversion definitions from the first retrieval condition, executes retrieval processing according to the generated second retrieval condition, and sends a retrieval result of the retrieval processing to the data retrieval/distribution client as a retrieval result according to the first retrieval condition.