To provide a packaging bag for heating in a microwave oven, wherein it is easy to fill contents, the contents can be safely cooked with heat without spilling, the bag is not peeled by pressure or shock applied during transportation or storage, steam is quickly discharged from the lowermost point of a point seal, an internal pressure can be automatically lowered, and the bag has self-supporting stability with good display effects in a shop and can be sealed with high productivity.

The packaging bag for heating in a microwave oven is a packaging bag with a bottom formed to be self-supportable obtained by folding both right and left sides of a composite film so that a sealant layer lies inward, forming a gusset having pleat-like folds inside, overlapping both ends of the folded composite film on one sides, heat-bonding to form a tube, and heat-bonding opposite sealant layers of the lower sides. A steam discharging means is formed above the contents filled in the bag while the packaging bag is supported by itself.