According to the present invention, the horizontal sections of the components of the condenser microphone are formed in an elliptical or a running track shape while the area of a diaphragm responding to sound pressure is maintained to be equal to or larger than a certain size, thus preventing a reduction in sensitivity to sound pressure as well as occupying the minimum internal space of each of various electronic products that trend toward miniaturization and thinness. Furthermore, a circular raised portion is formed at the center of the horizontal part of the casing, or a groove having an arcuate, triangular or rectangular section is formed on the horizontal part of the casing, so that the flatness of the casing and the gap between a diaphragm and a backplate are uniformly maintained, thus preventing the variations in the characteristics of the condenser microphone.