an apparatus for heat shrinking a heat - shrinkable plastic film wrapping a package includes a conveyor for conveying the package , a steam chamber arranged to cover the package on the conveyor at least from above , and a steam jetting pipe provided inside the steam chamber at an upper portion thereof for filling the steam chamber with steam . the package is conveyed to the location of the steam chamber by the conveyor and is introduced into the steam chamber where the plastic film wrapping the package is shrunk by heat given off by the steam .