Abstract: A tire pressure adjusting system of a vehicle includes: a sensor mounted in a tire, to measure pressure and/or temperature of air in the tire, and to send a signal corresponding to the pressure and/or temperature; a magnetic field generator mounted on the vehicle body near the tire, to receive the signal from the sensor, and to generate a magnetic field; a current generator mounted in the tire, to generate electricity by using the magnetic field; and an electric heating member mounted in the tire, to generate heat by using the electricity supplied from the current generator, thereby heating the air in the tire. A method of controlling tire pressure includes determining whether the pressure is too low; and, if the pressure is too low, heating air in the tire until the pressure is not too low.