An automatic dialing system includes a telephone directory database configured to store first terminal information which includes a first telephone directory and first identification information and second terminal information which includes a second telephone directory and second identification information. An instruction receiving unit is configured to receive a dialing instruction. A telephone directory search unit is configured to search for a telephone directory. A mobile device connection unit is configured to connect the second mobile device corresponding to the automatic dialing system, when the found telephone directory corresponds with the second telephone directory. A dialing control unit is configured to dial a phone number corresponding to the received instruction through the second mobile device, when the found telephone directory corresponds with the second telephone directory.