To provide a gloss retaining layer which shows radar range heat resistance and has a gloss showing a specific value or higher on one of the faces of a container thermally molded of a polypropylene multi-layer sheet after molding the container by setting the glossiness of at least one of the faces of the container at a specific value or higher and making it resistant to the heat of a radar range.

Polypropylene resins are classified as a propylene homopolymer obtained by homopolymerizing propylene and a copolymer obtained by copolymerizing monomer units, e.g. unsaturated organic acids such as ethylene and acrylate and anhydrides thereof with propylene. In the multi-layer sheet and the container formed of the sheet, at least one surface layer is a gloss retaining layer containing a crystal nucleator which retains gloss even after thermally molding the sheet. The crystal nucleator is of an inorganic or an organic material type such as talc or carboxylic acid metal salt. The addition dosage of the crystal nucleator is adjusted and also the glossiness after the thermal molding of the sheet is adjusted to be 40 or more. On the other hand, the multi-layer sheet is made resistant to the heat of a radar range.