A service providing system for providing a service to a communication terminal, the service providing system comprising: a communication object management part to associate with one another a plurality of pieces of terminal identification information for identifying differing communication terminals and to manage the plurality of pieces of terminal identification information, each of the plurality of pieces of terminal identification information including user identification information that is a to-be-authenticated section to be used to authenticate a user and is common to the plurality of pieces of terminal identification information, the communication object management part managing and associating the plurality of pieces of terminal identification information with one another as a piece of terminal identification information for a communication source and a piece of terminal identification information for a communication destination that can perform communication with the communication source; a receiving part to receive from a first communication terminal as a communication source a first piece of terminal identification information for identifying the first communication terminal and a second piece of terminal identification information for identifying a second communication terminal as a communication destination; and a transmitting part, in response to the receiving part receiving the first piece of terminal identification information and the second piece of terminal identification information, to transmit a request to the second communication terminal to start communication with the first communication terminal for a case where the first piece of terminal identification information and the second piece of terminal identification information are managed and associated with one another by the communication object management part and not to transmit a request to the second communication terminal to start communication with the first communication terminal for a case where the first piece of terminal identification information and the second piece of terminal identification information are not managed and being associated with one another by the communication object management part. a communication object management part to associate with one another a plurality of pieces of terminal identification information for identifying differing communication terminals and to manage the plurality of pieces of terminal identification information, each of the plurality of pieces of terminal identification information including user identification information that is a to-be-authenticated section to be used to authenticate a user and is common to the plurality of pieces of terminal identification information, the communication object management part managing and associating the plurality of pieces of terminal identification information with one another as a piece of terminal identification information for a communication source and a piece of terminal identification information for a communication destination that can perform communication with the communication source; a receiving part to receive from a first communication terminal as a communication source a first piece of terminal identification information for identifying the first communication terminal and a second piece of terminal identification information for identifying a second communication terminal as a communication destination; and a transmitting part, in response to the receiving part receiving the first piece of terminal identification information and the second piece of terminal identification information, to transmit a request to the second communication terminal to start communication with the first communication terminal for a case where the first piece of terminal identification information and the second piece of terminal identification information are managed and associated with one another by the communication object management part and not to transmit a request to the second communication terminal to start communication with the first communication terminal for a case where the first piece of terminal identification information and the second piece of terminal identification information are not managed and being associated with one another by the communication object management part.