An information processing system includes a terminal anonymizing data composed of records including one or more items through statistical processing, and a server storing the anonymized data set. The terminal includes a memory, and a processor configured to transmit an acquisition request which designates an acquisition condition to the server and acquire data which satisfies the acquisition condition from the server, create merged data, and transmit anonymized data obtained by anonymizing the merged data through the statistical processing to the server. The server includes a server memory, and a server processor configured to, in a case where the acquisition request is received, search for data which satisfies the acquisition condition from the data set and transmit data obtained as a result of the search to the terminal, receive the anonymized data, and subtract statistics included in the data transmitted to the terminal from statistics included in the received anonymized data.