Communication system and upload method

A communication system includes a plurality of communication terminals to transmit communication information and a communication controller. Each of the communication terminals includes: a generator to generate log information on communication between the communication terminals; a storage to store log information generated by the generator; and a transmitter to upload log information that is capable of being uploaded depending on a communication line band used for the communication information. The communication controller includes a communication management server configured to control transmission of the communication information and a log upload server, wherein the communication controller is configured to distribute the log information uploaded by the transmitter to the log upload server.