PURPOSE: To attain wireless communication between scuba divers and between scuba divers and ships by providing a small mode switch or a small keyboard on the end of a transmitter, and a sound synthesizer and bone conduction earphones on the end of a receiver.

CONSTITUTION: A diver has the small mode switch or the small keyboard 1, a modulator 2, a drive amplifier 3, etc., all of which are loaded on his arm as a transmission means, and has a preamplifier 6, a demodulator 7, a word and sound synthesizer 8, the bone conduction earphones 9, etc., as a reception means, and further has a circulator 4 to transmit and receive waves, a transducer 5, etc. Necessary words such as 'Watch out.' and 'Go up.' that mean signals between divers or between divers and ships are prepared beforehand, and code signals to mean the words are transmitted. On the reception side the word and sound synthesizer is provided, and corresponding words and sounds are synthesized by the synthesizer according to the transmitted code signals, led to the bone conduction earphones and reported to a receiving party.