A method of easily deforming a plate-shape vacuum insulation material and producing a smaller but highly effective insulation container, comprising steps of inserting a thermoplastic open-celled rigid foam as a core material into a packet composed of gas barrier film, evacuating and sealing the packet so as to produce a vacuum insulation material, heating and softening the vacuum insulation material so as to deform the same, and cooling the vacuum insulation material so as to cure the same, and also a freezing and refrigerating container having Peliter element.