To ensure the easy disposability and easy combustibility, to eliminate the odor generation, and to improve the productivity by using a composite paper in which a paper is stuck to both sides of a foam resin layer in forming a layer of at least a body part in a paper cup comprising the body part and a bottom part in which a circumferential edge of an opening part is curved outside.

A heat insulated paper cup comprises a body part 11 and a bottom part 12, and a circumferential edge of an opening part has an outwardly curled mouth edge part 13. At least the body part 11 is of the layer constitution using a composite paper 1 in which papers 3, 4 are stuck to both sides of a foam resin layer 2. A body member to form the body part 11 is formed of a converted paper in which a polyethylene resin 5 is laminated on one side of the composite paper 1 where the papers 3, 4 are attached to both sides of the foam resin layer 2. The foam resin layer 2 is formed by adding a thermal foaming agent 2b to a polyolefin resin 2a of a main component, and kneading them. In addition, a raw cup paper can be preferably used for the papers 3, 4 to be stuck to both sides of the foam resin layer 2.