A silicon condenser microphone having an additional back chamber and a sound hole in a PCB is disclosed. The silicon condenser microphone in accordance with the present invention comprises a case for blocking an inflow of an external sound; a substrate including a chamber case, a MEMS chip having an additional back chamber formed by the chamber case, a ASIC chip for operating the MEMS chip, a conductive pattern for a bonding to the case, and a sound hole for passing the external sound therethrough; a fixing means for fixing the case to the substrate; and an adhesive for bonding the case and the substrate, wherein the adhesive is applied to an entirety of a bonding surface of the case and the substrate fixed by the fixing means. Therefore, when the sound hole is formed through the PCB instead of the case, the microphone may be mounted in various ways, thereby reducing a mounting space, and the chamber case for forming the additional back chamber under the MEMS chip is employed in order to increase a back chamber space of the MEMS chip, thereby improving a sensitivity and a noise problem such as a THD (Total Harmonic Distortion).