Telephone conference system

A telephone conference system comprising:

• a conference circuit configured to allow a plurality of registered telephones registered in advance to make a call to each other;
• a telephone exchange storing a telephone number of each of the plurality of registered telephones and is configured to connect the plurality of registered telephones to the conference circuit;
• and
• a selection device;
• wherein when a reception telephone connected in advance to the conference circuit receives a call from an external telephone, the telephone exchange is configured to connect the external telephone to the conference circuit, and connect a first registered telephone predetermined from among the plurality of registered telephones to the conference circuit,
• the selection device is configured to allow a user of the first registered telephone to select a second registered telephone to be connected to the conference circuit from among the plurality of registered telephones, and
• the telephone exchange is configured to connect the second registered telephone selected by the selection device to the conference circuit.