PURPOSE: To prevent a flap from being swelled through the valve hole of a rim by connecting multiple reinforcement elements arranged in a direction crossing a stem so that they can be moved to and from the stem, and providing a reinforcement plate covering a space between the valve hole of the rim and a bridge washer.

CONSTITUTION: A metallic piece 36 of a reinforcement member 32 is fixed onto a rubber base 30 at the foot of a stem 24 of a tube 10 for a pneumatic tire with a nut 26. The reinforcement member 32 is formed with a metallic piece 36 used commonly for bridge washer and multiple metallic wires 40 arranged in the direction crossing the stem 24. The metallic wires 40 are connected to each other by means of a rubber material 42 so that they can be moved to and from the stem 24. Accordingly, when the tube 10 for pneumatic tire is assembled in the rim 24, a valve hole 28 for the rim 24 can be covered with the reinforcement member 32. Thus a flap 22 can be prevented from being swelled to the inside of the rim 18 through the valve hole 28.