To obtain a simplified container which can prevent a lid thereof from slipping off due to deformation of the whole of a container body generated when the container is heated, while heat-insulating properties as a simplified container being maintained, and which has also a good external appearance.

A main body 1 of the simplified container 10 for foods consists of an inner container 3 comprising a thin-walled integrally molded heat-resistant plastic body and an edge frame 4 made of foamed plastics. A first heat- insulating space 51 is formed between an extending part 31 from the periphery 32 of the upper edge of a rising part 33 whose lower end is thermally bonded to the lower end of the frame 4 and the inner surface of the edge frame 4. A second heat-insulating space 52 is formed between the rising part 33 of the inner container 3 and the extending part 31. A double heat-insulating space comprising the first heat-insulating space 51 and the second heat-insulating space 52 is provided between the inner container 3 and the edge frame 4. An engaging mechanism 6 is formed at the part 31 from the periphery 32 of the upper edge of the container 3 at a corner B and at the periphery of a cap member 2.