HEAT INSULATING CONTAINER

PURPOSE: To use a foaming synthetic resin heat insulating container suitably for seat extension to fill the rear seat of an automobile without causing the possibility of cracking or breakage even if large load is applied from the above, by constructing the heat insulating container so as to set a partition plate disposed inside the container at a prescribed position with high stability and attain complete reinforcing of a cover. CONSTITUTION: At least a pair of recessed grooves which continue to an upper opening from the top of a bottom part 1 l are formed at the inner surfaces of two side walls facing each other in a container body 1, and at least a pair of recessed grooves which continue to the lower surface of an upper plate part 21 from the opening of a cover 2 are also formed at the inner surfaces of the side walls corresponding to the recessed grooves 13, 13 in the container body of the covered article 2. By fitting a partition plate 3 into the recessed groove, both upper and lower ends 32, 31 are disposed so as to be jointed to the upper surface of the bottom part 1 1 of the container body 1 and the lower surface of the upper plate part 21 of the covered article 2.