In a high-pressure tank 1 in which a gas discharge section 5 is extended from one end of a cylindrical section 2 through a dome section 4 by plastically deforming a short hollow cylindrical blank of metal, the gas discharge section 5 is set at a thickness at least three times that of the cylindrical section 2, and the dome section 4 is gradually increased in thickness from that of the cylindrical section 2 to that of the gas discharge section 5 in proceeding from the cylindrical section 2 to the gas discharge section 5. Thereby, a high-pressure tank capable of withstanding higher pressures than used at the present time is provided easily and at low cost.