A film is used in a package in which the internal pressure of a container increases when heated in a microwave oven, and the internal pressure is reduced by releasing internal steam. The film includes: an outer layer film molecularly oriented by biaxial stretching; an inner layer film that is laminated to the outer layer film and heat-sealable; one or more orientation relaxation portions formed in the outer layer film, and a breaking portion provided at a position which the one or more orientation relaxation portions face with a predetermined distance and configured to rupture when the internal pressure of the container is increased in the microwave oven. At least the breaking portion omits a printed layer between the outer layer film and the inner layer film.

Provided is a microwavable pouch having a rectangular outer shape in plan view. The microwavable punch includes an automatic steam release mechanism. The automatic steam release mechanism includes a steam release portion and a steam release seal portion surrounding the steam release portion, and assuming that there is an inscribed ellipse in contact with centers of inner edges of sides of a peripheral seal portion of the pouch, the steam release seal portion is formed so that a circumference of the inscribed ellipse is positioned in a width region of a seal separation start portion of the steam release seal portion closest to a center point of an accommodation portion or in a vicinity of the seal separation start portion.