The present invention discloses a microphone comprising a first electrode, a second electrode, a printed circuit board and a shielding layer. The microphone is configured into a mobile communication device. The shielding layer located on the printed circuit board is disposed on the microphone. When the mobile communication device charges with an AC power supply and communicates with others simultaneously, the shielding layer can diminish the 50˜60 Hz noise produced by the AC power supply. Owing to the shielding layer reduces the EMI effect; the talking quality of the mobile communication device is thereby enormously improved.