A tire inflation pressure sensing apparatus according to the present invention includes a transmitter and a receiver. The transmitter is provided on a wheel of a vehicle and includes a pressure sensor working to sense an inflation pressure of a tire on the wheel and an acceleration sensor working to generate a signal as a function of a component of gravitational acceleration in the sensing direction thereof. The transmitter is configured to determine a position thereof depending on the signal generated by the acceleration sensor and transmit the signal representative of the inflation pressure of the tire toward the receiver when a transmitting request is issued and the determined position thereof falls in a predetermined range. The receiver is provided on the body of the vehicle and is configured to receive the signal transmitted from the transmitter and determine the inflation pressure of the tire depending on the received signal.