A communication system comprising: a connection control apparatus configured to receive a connection request message that requests a connection to a network from a first communication apparatus included in a plurality of communication apparatuses in which a synchronous communication is limited and allow the first communication apparatus to be temporarily connected to the network when the connection request message corresponds to a message that requests a temporary communication; and a communication timing control apparatus configured to transmit, when the communication timing control apparatus receives a communication timing request message that requests acquisition of the communication timing from the first communication apparatus while the first communication apparatus is allowed to be temporarily connected to the network, a communication allowable timing notification message indicating a communication timing to the first communication apparatus while the first communication apparatus is allowed to be temporarily connected to the network; wherein the communication timing control apparatus is configured to start a collective accept timer when the communication timing control apparatus receives the communication timing request message from the first communication apparatus, and when the communication timing control apparatus receives the communication timing request message from a second communication apparatus included in the plurality of communication apparatuses while the collective accept timer is being activated, calculate a communication timing of the second communication apparatus and update the communication timing of the first communication apparatus. a connection control apparatus configured to receive a connection request message that requests a connection to a network from a first communication apparatus included in a plurality of communication apparatuses in which a synchronous communication is limited and allow the first communication apparatus to be temporarily connected to the network when the connection request message corresponds to a message that requests a temporary communication; and a communication timing control apparatus configured to transmit, when the communication timing control apparatus receives a communication timing request message that requests acquisition of the communication timing from the first communication apparatus while the first communication apparatus is allowed to be temporarily connected to the network, a communication allowable timing notification message indicating a communication timing to the first communication apparatus while the first communication apparatus is allowed to be temporarily connected to the network; wherein the communication timing control apparatus is configured to start a collective accept timer when the communication timing control apparatus receives the communication timing request message from the first communication apparatus, and when the communication timing control apparatus receives the communication timing request message from a second communication apparatus included in the plurality of communication apparatuses while the collective accept timer is being activated, calculate a communication timing of the second communication apparatus and update the communication timing of the first communication apparatus.