Problems concerning adhesion strength and aging time are eliminated in plastic-bag production in which a strip sheet is bonded with an adhesive and a handle is formed from the strip sheet on an outer surface of a plastic bag. Provided is a bag-making machine in which a strip sheet (17) and a web material are disposed so as to face each other and are pressed, with a high-adhesion adhesive (21) and another adhesive (25) interposed therebetween. The strip sheet (17) is provisionally fixed to the web material with the latter adhesive (25). This web material after the provisional fixing is wound on a roll, and a plastic bag is produced after lapse of an aging time for the high-adhesion adhesive (21). In this machine, the web material is supplied from the roll, and a plastic bag is produced from the web material.