The transmission speed of downlink communication information to be received by communication terminals has been improved. A mobile communication system comprises a plurality of communication terminals that wirelessly communicate with each other; and a base station that is requested, based on the transmission speeds of the communication terminals, by the communication terminals to transmit downlink communication information. Each local communication terminal has a relay requesting device that receives information on the transmission speed of another communication terminal and that, when the transmission speed of the other communication terminal is greater than that of the local communication terminal, transmits, to the other communication terminal, identification information to be used for the base station to identify the local communication terminal or the other communication terminal, thereby requesting the other communication terminal to relay communication information addressed to the local communication terminal. The base station has a terminal identifying/transmitting device that transmits, based on the identification information of the local communication terminal, the communication information addressed to the local communication terminal to the local communication terminal via the other communication terminal.