Multiple tires are mounted adjacently parallel to each other on a single wheel. Respective inner spaces of the multiple tires communicate with each other by way of an airflow pipe for the transfer of air. The airflow pipe includes a pneumatic pressure control valve that opens or closes in response to air leaking from one or more of the multiple tires. When one of the multiple tires leaks air rapidly, the pneumatic pressure of the other normal tire decreases, thereby forcing the driver to notice the puncture. If one tire leaks air slowly, its air is replenished from another tire. Thus the respective pneumatic pressures of the individual tires become equal, whereby the driver can continue to drive for a time without risking the serious accident that could occur if he were unaware of the leak.