To envelop a highly heat-insulating and sound-insulating honeycomb structure which is best suited for mass-production in a short time and does not require a long time n production or manufacturing, taking advantage of the properties such as light weight and high strength of the honeycomb structure and whose material and manufacturing costs are low.

This structure comprises a honeycomb structure 10 as a core material, a thermoplastic resin 20 which is present as an interposed layer on both front/back faces 12 through which each of holes 11 of the honeycomb structure 10 is opened and an integrally molded foam resin 30 which is present as an enveloping material wrapping the whole honeycomb structure 10 with the thermoplastic resin 20 interposed on the front/back faces 12. In this case, the honeycomb structure 10, the thermoplastic resin 20 and the foam resin 30 are continuously joined together at their borders.