The present invention provides a reinforced lightweight air bladder for a safety tire which can effectively suppress a radial growth under the normal running condition even if it is used for a long tire and, on the other hand, to suppress an occurrence of a crack in a tube under the runflat running condition, thereby exhibiting a superior durability. A hollow toric reinforced air bladder 1 is to be accommodated in a tire 2 to form a safety tire. The reinforced air bladder 1 is filled with the air at an internal pressure determined in relation to a given air pressure of the tire 2 to form a cavity S1 in tire 2. When the internal pressure of the cavity S1 of the tire 2 is dropped due to getting punctured or the like, the reinforced air bladder 2 is radially expanded to take over load support from the tire 2. The reinforced air bladder 1 comprises an air-impermeable tube 6 and a reinforcing hoop layer 7 surrounding entirely an outer circumference of a crown portion of the tube 6. The reinforcing hoop layer 7 is made of a low tension resistance material.