Provided is a mask apparatus. The mask apparatus includes a mask body in which a microphone and a speaker are installed, a face guard coupled to a rear surface of the rear body so as to be in close contact with a user's face and having a breathing space therein, a pressure sensor installed in the mask body to measure a pressure of the breathing space, and a controller configured to compare a current pressure value measured by the pressure sensor to a reference pressure value and control a voice output of the speaker based on a difference between the current pressure value and the reference pressure value.