To prevent a film from being damaged and retain a folding margin even if a fold initially performed is deep by performing an initial fold only at a center of an object to be packaged mounted on a packaging part or only the center and an end by a folding roller.

An object H to be packaged which has been carried to immediately below a packaging part D is projected vertically toward a film 30 extended at a predetermined position of the packaging part D by a conveyer table 20. Left and right folds 41a, 41b move to the center approximately simultaneously as release of left and right clamps 43a, 43b and stop with a slight distance between them at a bottom center of the object H. Approximately simultaneously as this, front and rear fold plates 40a, 40b start moving toward the center. Further, following this, front and rear grippers 32, 33 come close to each other, and film contact faces of the front and rear fold plates 40a, 40b come into contact with each other, thereby completing folding. The object H is taken out from the packaging part D, and folding margins 52, 53 are heat-sealed.