To make it possible to appropriately and continuously subject heat exchange process by a liquid medium to an article to be packaged in a state not entering the liquid medium into an unsealed part of a packaging bag.

This is a device for subjecting the heat exchange process to a belt-shaped continuous body 105 which is comprised of a plurality of packaging bags 106 continuously formed by subjecting thermal seal 107 along in a transfer direction x to a packaging film 100 transferred in a twofold state while transferring in a continuing direction. The device is provided with a treating vessel 1 wherein a liquid medium W is stored and a guide means 4 which guides the belt-shaped continuous body 105 so as to soak in the liquid medium of the treating vessel 1 in the process of transformation. The guide means 4 is provided with a travelling body 40 to form an endless body, and a plurality of clip bodies 41 which are mounted on this travelling body 40 and transferred and clips the belt-shaped continuous body 105 so as to be able to support in a hanging state with the edge part 102 on a facing side to a folded side 101 faced upward.