To provide a microphone which has a precise structure which is operated accurately during a thunderstorm and which is developed originally for providing to a market, whereby a distance between cars can be immediately and accurately measured and displayed under a bad weather, thereby decreasing traffic accidents vastly.

In a structure of an amphibious waterproofing microphone of an electret capacitor structure, the microphone is protected by a certain unique waterproofing film having water non-permeability and sound passing capability, and a weather resistance sheet of a multilayered structure in which a reflected sound is transmitted to an electret microphone by air vibrations by use of a resilient pressure resistance pad, to be converted into an electric signal.