PURPOSE: To provide a bag feeder of a packing machine by which various kinds of bags are securely fed to a packing machine one by one regardless of characteristics of respective bags and information by printing or the like can be smoothly given on the sealing part of the bags.

CONSTITUTION: A transfer shaft is rotated to force the surface of a bag S to contact the arced face of a pressing member 22, in a state that the side edge of one of surfaces of a superposed bag S is sucked by a suction device 21 to transfer this bag S from the delivery position to the feed position. In this feed position, a projected part sideward from the pressing member 22 of the bag S is placed on the loading base 30. Informations like the production date can be smoothly printed on the part of bag S placed on the loading base 30.