There is proposed a non-self supporting type flexible package bag provided with a film-shaped one-way pouring nozzle, which is excellent in not only the non-return function and liquid cutting properties but also the pouring property of a liquid packed material as a filling material (packed material in the bag can be poured smoothly until the end). In the flexible package bag provided with the film-shaped one-way pouring nozzle protruding from a side portion, corner portion or top portion of the package bag body, a coating layer made from a water-repellent material or an oil-repellent material is provided on an outer surface of the film-shaped one-way pouring nozzle, while a wet-treated layer is provided on an inner face of a pouring path in the film-shaped one-way pouring nozzle.