A communication device enables a voice communication with another communication device connected to a communication circuit network. The communication device has a calling signal detection system that detects whether a calling signal is received from the other communication device via the communication circuit network, a circuit closing system that is configured to close a circuit connecting the communication device and the other communication device when a communication starting operation is performed by a user after the calling signal detection system detects the calling signal from the other communication device, a state detection system that detects whether the calling signal currently received is in ON or OFF state, and a standby control system that controls the circuit closing system to await closing the circuit until the state detection system detects the OFF state of the calling signal if the state detection system detects the ON state of the currently received calling signal.