<p>A packaging bag with a steam-venting-related improvement is provided. Said packaging bag has a seal part (8a) formed where an edge of a film that constitutes a top surface and an edge of a film that constitutes a bottom surface are sealed together. This packaging bag is characterized by having a steam-venting seal part (7) that comprises part of the aforementioned seal part (8a) formed so as to protrude inwards with a curved shape. This packaging bag is further characterized in that: the width of the seal, at least in the direction inwards from the abovementioned seal part (8a), is narrower at the tip of the steam-venting seal part (7) than in the other sections of the steam-venting seal part (7); and when the packaging bag inflates and the steam-venting seal part (7) comes apart, the aforementioned other sections thereof remain and form edge parts (7a) protruding inwards from the seal part (8a).</p>
