A communication system includes a first terminal, a second terminal, and a third terminal. The first terminal transmits message data addressed to the third terminal to plural terminals. When the second terminal receives the message data and confirms that a destination thereof is not the second terminal, the second terminal transfers the received message data. When the third terminal receives the message data and confirms that the destination thereof is the third terminal, the third terminal transmits response data corresponding to the received message data to the first terminal. A priority for transmission of the response data is set higher than that of the transferred message data, and a period of time from reception of the message data until the transmission of the corresponding response data is shorter than a period of time from reception of the message data until the transfer of the message data.