A communication device belonging to a first cluster among a plurality of clusters includes a memory, a processor, and a network connection device. The memory stores identification information of another cluster that has information being retrievable by a terminal connecting to the communication device in a summary of data held by the other cluster. The processor performs, upon receiving a combination of identification information of a second cluster that holds retrieval-target data and identification information of the retrieval-target data from the terminal that accessed the summary, a control to request target data identified by the combination. The network connection device forwards the target data to the terminal.