A radiation sterilization method of a disposable medical device and a manufacturing method are provided, which method comprising the steps of packaging a disposable medical device, which has applied thereto with hydrophilic polymer coating, with a gas permeable packaging material, controlling a product moisture content of the thus packaged medical device by maintaining the device in a given humidity atmosphere for not less than a time at which an equilibrated moisture content is reached, and subjecting, to radiation sterilization, the medical device whose product moisture content has been controlled, so that an eluted matter is reduced in amount and a sliding performance is ensured according to the radiation sterilization method of the hydrophilic polymer-coated, disposable medical device and the manufacturing method.