Abstract: The invention relates to an overpressure protector comprising a body portion (1) of single crystal silicon, a burst flow conduit (2) extending through the body portion (1), and a membrane (3) covering the burst flow conduit (2) and responding to a pressure difference. The membrane is a thin film (3), which is arranged to break when the pressure difference acting across it exceeds a predetermined value, and comprises a belt (6) whose electrical conductivity differs from that of the other material of the membrane. The belt is connected to means (9) for supplying electric current either for detecting breaking or the belt or for bursting the membrane (3) intentionally by means of heating effect of electric current.