PURPOSE: To prevent the remaining of undesirable marks based on the fold of a film even when a cylindrical shrinkable film having a fold was used, by forming specific relation between the outer diameter dimension of an auxiliary jig in the diameter direction, the inner diameter dimension of a shrinkable film in the diameter direction corresponding to said outer diameter dimension and the outer diameter dimension of an article in the diameter direction.

CONSTITUTION: The relation of 3<1<2 is formed between the outer diameter dimension 1 of an auxiliary jig in the diameter direction, the inner diameter dimension 2 of a shrinkable film in the diameter direction corresponding to said outer diameter dimension 1 and the outer diameter dimension 3 of an article in the diameter direction. The film 12 is supplied from above in a folded state and sufficiently spread by an upper auxiliary cylinder 8 to be formed into a cylindrical shape. Therefore, the film 12 is inserted without being contacted with the surface of a base body. Because both ends of the film 12 are supported by the auxiliary cylinders 8, 10, shrinkage is started from the central part of the film 12 at first and a shrinking region is gradually enlarged to both end parts to perform good covering.