In a content-log analyzing system, content includes additional information indicating, according to a property of the content, whether or not to record communication of the content in a content-log. When transmitting content to a TV or a PC, a data-communication controlling device judges whether or not to record the communication in a content-log based upon additional information of the content, and when judging affirmatively, generates and stores content-log information. A content-log analyzing server obtains the content-log stored in the data-communication controlling device, and analyzes the obtained content-log.