A portable communication terminal control system includes a plurality of first portable communication terminals and a second portable communication terminal. A first processor in the first portable communication terminal performs a first portable communication terminal side determination process which determines whether communication connection is in an established state between a first portable communication terminal and the second portable communication terminal. The first processor performs a transmission control process in which, in response to determination that the communication connection with the other first portable communication terminal is in the established state and that the communication connection with the second portable communication terminal is in the established state, a release signal is transmitted to the second portable communication terminal. The second portable communication terminal includes a second processor which, in response to receiving the release signal, shifts the second portable communication terminal to the released state.