Provided is a communication system that includes an electronic timepiece and a communication apparatus, in which, when the electronic-timepiece communication unit demands a communication connection to the communication apparatus, the communication-apparatus control unit inquires whether or not the electronic timepiece is included in the connection approval list that is stored in the communication-apparatus storage unit, in which, in a case where the electronic timepiece is included in the connection approval list, the communication-apparatus communication unit establishes a communication connection to the electronic timepiece and performs data communication through which at least clock time data is sent to the electronic timepiece, and in which, in a case where the electronic timepiece is not included in the connection approval list, the communication-apparatus communication unit does not establish the communication connection to the electronic timepiece.