To provide a pressure-regulated calling device capable of eliminating degradation of the voice transmission performance by the use of a strong diaphragm of a microphone and a speaker integrated with a pressure-proof vessel, attenuation of the voice vibration caused by the water pressure on the diaphragm caused as the diving depth is increased, and the service depth limit determined by the pressure-proof performance of the vessel, and transmitting consistent sound information underwater.

A microphone vessel 5 and a speaker vessel 4 are mounted on a mouth mask 2 with a water ingress preventive vessel 3. A mask internal cavity 12 to which air of the same pressure as the ambient pressure is supplied from a secondary pressure reducing valve 1 of a regulator, a microphone vessel internal cavity 15 and a speaker vessel internal cavity 14 are connected to each other via a vent pipe to equalize the pressure in the respective cavities. As a result, the differential pressure between the inside and the outside of the vessels is eliminated, and a problem of attenuation of the voice vibration and the service limit by the diving depth is solved. At the same time, any high pressure-proof strength is not required in external diaphragms 19, 20 of the microphone and the speaker forming a part of the vessels, and a thin diaphragm to facilitate the voice vibration can be used.