Breathing apparatus comprising a body in the form of a mask shaped to be worn over a portion of a user's face, a breathing passage formed in the body having an outlet in one end only in communication with one of either the nose or the mouth of the wearer and having an inlet at the other end thereof, a container holding a quantity of gas for breathing adapted for connection to the mask body with the container outlet in communication with the breathing passage and the container releasing a flow of gas to the breathing passage when connected to the body, an exhalation passage defined by the body in communication only with the other of the mouth or nose of the user and being open to the atmosphere, and a mouthpiece element associated with the passage leading to the mouth and adapted to be received between the teeth of the wearer in gripping engagement to facilitate holding the apparatus in place on the head of the user. As a result, the user does not inhale from and exhale to the same chamber of the mask, and in the event straps or other conventional holding members on the mask should break, the user can hold the mask in place using his teeth. There is provided also a valve for controlling the flow of gas from the container as it is connected to the body.