HEAT-INSULATING BOX MADE OF PAPER

PROBLEM TO BE SOLVED: To provide a heat-insulating box made of paper, which has a high efficiency of containing a product while maintaining a heat-insulating effect. SOLUTION: An outer box 3 of the heat-insulating box is composed of a pair of first side sheets 9 opposed to each other, each erecting from a longer side edge of a bottom sheet and having a first top surface sheet 23 extending at an upper part of the first side sheet 9 and a first suspension sheet 27 suspending from the first top surface sheet 23, a pair of second side sheets 13 opposed to each other, each erecting from a shorter side edge of the bottom sheet and having a second top surface sheet 31 extending at an upper part of the second side sheet 13 and a second suspension sheet 35 suspending from the second top surface sheet 31, and corner sheets 17 for connecting both ends of the first and second side sheets to one another. After triangularly folding the corner sheets back to erect the first and second side sheets with respect to the bottom sheet, the first and second top surface sheets are folded back in a plane manner, and an upper interval between the first side sheets is made narrower than a lower interval therebetween to assemble the first side sheets so as to be formed into a trapezoidal shape when viewed from the side of the second side sheets. In an inner box 15 of the heat-insulating box, third side sheets 45, which are butted to each other to form a bottom sheet for closing a bottom surface at their lower portions, and fourth side sheets 47, which form bottom sheet pieces at their lower portions, are erected along the first and second suspension sheets, and a gap to be produced by the trapezoidal shape is made definable between each first side sheet and each third side sheet, respectively.