The invention provides an autoclave capable of creating a uniform temperature distribution inside a pressurized chamber and a method for manufacturing tires using the autoclave. The autoclave shaped as a cylindrical pressurized chamber has a heat source and a fan disposed on one end side thereof and ducts extending lengthwise on the inner peripheral wall surface thereof to discharge air blown by the fan to the other end side thereof. And the air outlets of the ducts are so designed as to discharge the air blown by the fan in a circumferential direction of the pressurized chamber.