PURPOSE: To securely insert an article to be inserted into a bag in a process for shrink-packaging the article such as a tube, a can or a bottle.

CONSTITUTION: A lower face layer 25 of a bag 15 made of a shrinkable film is sucked to be fixed by a lower face sucking body 26. In addition, an upper face sucking body 28 for sucking to fix an upper face layer 27 of the bag 15 is pulled up to open an opening 14 of the bag 15. Tips of a pair of guide plates 35 facing each other in a -shape are inserted and located in the opening 14, an article 3 to be inserted which is located at a holding space 34 between the guide plates 35 is pushed toward the opening 14, and while the holding space 34 is pushed to expand, the article 3 is inserted into the bag 15.