PURPOSE: To decrease the number of components and to facilitate the fixing work by providing a sensor body housing a pressure switch and an oscillator, and a compliant sensor housing comprising a tubular part and a bottom part closing one end thereof with a rim clamping part being provided on the outer circumferential face thereof.

CONSTITUTION: The pneumatic pressure sensor 100 for tire comprises a sensor body 101 and a sensor housing 102 wherein the body 101 comprises a base part 101A, and a forward end part 101B having outer diameter larger than that of the base part 101A coupled concentrically each other. The sensor 100 is fixed to the rim 2 of a tire 1 such that a pressure detection means is disposed in the tire 1. Antenna coil 4 of an inner pressure detector for tire is fixed to a brake cover 3 while being disposed oppositely to the sensor 100. The coil 4 is connected with a receiving unit 5 in the inner pressure detector through a lead wire 6. The unit 5 radiates electromagnetic wave through the coil 4 toward the sensor 100 and the inner pressure of tire is checked based on an echo signal received by the sensor 100.