To stabilize bagging operation of sandwiches or the like and fully automate a product production process by providing a loading mechanism having a tray transfer means which transfers a tray on which the sandwiches or the like can be mounted into a packaging bag which has already opened and a position adjust mechanism which can transfer the sandwiches or the like on a conveyer onto the tray.

A detection means 7 senses that a sandwich S or the like has been transferred to a tray 2a of a loading mechanism 2 by a conveyer 1. A position adjust mechanism 3 advances a back-pushing part 3a with a signal from the detection means 7 for pushing the sandwich S or the like until its tip is aligned with a tip of the tray 2a and transferring it from the conveyer 1 onto the tray 2a. Subsequently, the loading mechanism 2 is driven to advance a tray transfer means 2b for casing the sandwich S or the like together with the tray 2a into a packaging bag by an opening mechanism 5. Then the tray transfer means 2b is further advanced to a package posture changing mechanism 6, and the bagged packaging bag is cut off from a packaging bag supply mechanism 4 to be received into a bucket 6a.