<p>An easily openable packaging bag which does not produce small pieces of debris when opened, which can be easily opened even by one hand, and which can be applied to a packaging bag having barrier properties. To form the packaging bag, opposite ends of a packaging material are joined together to form the material into a tubular shape and the joined opposite ends are heat sealed to form a bonded and joined rear section located on the rear side of the tube section. Inside the tube section are contained solid contents. Of those portions of the tube section, a portion not occupied by the contents is provided with a weakened section formed in the circumferential direction of the tube section so as to extend in a portion thereof excluding at least a portion of the bonded and joined rear section.</p>
