Abstract: An air floater comprises a balloon body which seals a gas therein and balancing means detachably attached to the balloon body. The balloon body comprises a film composed of a central layer made of ethylene-vinyl alcohol copolymer-resin, an aluminum evaporated layer provided outside the central layer, and a heated adhesive layer provided inside the central layer. The balancing means comprises a plurality of magnetic cards which are attracted by an attraction portion composed of a magnetic body attached to the balloon body. The plurality of magnetic cards includes one card having a reference weight matched with the buoyant force of the balloon body, first weight balancing cards having weight heavier by stages than the reference weight, and second weight balancing cards having weight lighter by stages than the reference weight. The balancing means may comprise sublimate sealed in a bag body.