PURPOSE: To inject compressed air into a tire during its rotation by arranging a circular and flexible hose on the inside periphery of a wheel rim, and rotating a presser locally compressing the flexible hose relatively to the tire.

CONSTITUTION: A flexible hose 3 is arranged on the inside periphery of a wheel rim 1, the contraction generated by locally squeezing the flexible hose 3 is moved from an orifice 31 communicated with the atmospheric pressure toward an orifice 32 on the opposite side opened into a tire 2, then the air required for injection into the tire 2 can be compressed. At the time of air injection, a roller 5 pressed to the rim 1 side by an electromagnet or a fluid operating means is rotatably supported to function as a presser. A check valve 4 is provided at the outlet opening portion of the orifice 32, the check valve 4 is opened via a tappet 7 when another roller 6 is pressed to the rim 1 side, then the tire 2 can be deflated.