Abstract: There is provided a data management server that is connectable to a plurality of content servers that store content data and metadata that includes content data attribute information and to a client device that acquires the content data based on the metadata. The data management server includes a data collection portion, a data processing portion, and a transmission portion. The data collection portion collects the metadata from each of the plurality of the content servers. The data processing portion hierarchically structures the metadata that the data collection portion collected, based on the attribute information that is included in the metadata. The transmission portion, in response to a request from the client device, transmits to the client device the metadata that was hierarchically structured by the data processing portion.