A monitoring device for portable breathing apparatus has a manometer that detects the pressure in the pressure reservoir (5) of the breathing apparatus and an emitter (2) that emits at regular intervals a signal that corresponds to the pressure. The emitter further has a signal generator that generates an identification signal charactheristic for the emitter. The pressure signal and the identification signal are received and checked by a receiver (3). When the identification signal matches an identification comparison signal stored in the receiver, the pressure measurement value is displayed on a display (4).