In a packaging machine, a pair of shutter members holds a tubular film therebetween and shakes the tubular film. Articles on an upstream side of the shutter members within the tubular film therefore aggregate toward the side of the shutter members while the vibration of the shutter members causes the gaps between the packaged articles to be filled. Since the packaged articles aggregate by inertia due to the vibration, fragmentation thereof is less likely than in a case in which the packaged articles are compressed by direct contact. Merely by the movement of rollers on a waved surface of a shutter cam, the shutter members are shaken in accordance with the waved surface.