Abstract: A warning device for tire pressure anomalies in which the valve of the tire to be monitored is connected to a pressure variation sensor which has two pressure thresholds, one for insufficient pressure, the other for excess pressure. When one of the thresholds is reached, the sensor closes an alarm circuit connected to an electronic signalling circuit on a printed circuit fixed on a sealed casing that is rigidly connected to the frame of the wheel and which contains two batteries that supply the signal transmission circuit. The data delivered by the signalling circuit is sensed by a detector that supplies a series of frequency selectors that discriminate the tire for which a warning is given for excess or low pressure. In the case of a pressure anomaly, the frequency severally command a relay that energizes a signal light and triggers an acoustic signal.