PURPOSE: To accommodate a person in a balloon for life-saving, sport, business or the like by incorporating inner and outer bladders in a balloon and by defining a space for accommodating a person, in the inner bladder.

CONSTITUTION: A balloon incorporates an inner bladder 2, an outer bladder 3 and a accommodation chamber 4 for an escaping victim or the like defined in the inner bladder 2. The inner bladder 2 is formed of more than one layer of balloon shape membrane members at the innermost side of the balloon, and the accommodation chamber 4 is defined in the inside of the inner bladder 2. The outer bladder 3 is formed of more than one layer of membrane members and an air space defined between these membrane members and the outer periphery of the inner bladder 2. The accommodation chamber 4 defined in the inside of the bladder 2 is formed of membrane members joined to the membrane members constituting the inner bladder 2, and is recessed into the inner bladder 2 from an entrance for the chamber. Further, means for forcibly forming and holding the shape of the accommodation chamber 4 is provided between the outermost one of the membrane members forming the accommodation chamber and the innermost one of the membrane members forming the inner bladder 2.