Disclosed is a gas tank having a gas-barrier inner shell and an outer shell which is so formed as to cover the inner shell and made of a pressure-resistant FRP. The gas tank is characterized in that the outer shell is composed of (A) a reinforcing fiber bundle, (B) a thermosetting resin and (C) elastomer particles and/or thermoplastic resin particles, and the elastomer particles and/or thermoplastic resin particles (C) dispersed in the thermosetting resin (B) are present within the reinforcing fiber bundle (A). This gas tank is excellent in strength and heat resistance, while having suppressed gas permeability.