To obtain a cushioning heat-insulating material having a homogeneous foamed state not changed also after dried, by beating a cellulose substance or waste paper, dehydrating the beat paper up to a specific water content, mixing the dehydrated product with an adhesive and a foaming agent, heating the mixture at a specific temperature, charging the heated mixture into a mold, irradiating the charged mixture with microwaves, and subsequently drying the irradiated molded product by a specific drying method.

This new method for producing the cushioning heat-insulating material comprises beating a cellulose substance or waste paper, dehydrating the beat paper up to a water content of about 25 wt.%, mixing the hydrated paper with an adhesive (e.g. a starch paste) and a foaming agent (e.g. azodicarbonamide) preferably in amounts of 0.1-20% and 0.5-20%, respectively, preliminarily heating the pre-mixture at about 50-100°C, charging the dried pre-mixture into a mold, irradiating the charged pre- mixture with microwaves to homogeneously foam the molded product, and subsequently uniformly maintain the inner temperature of the foamed product at about 50-100°C by the utilization of P.T.C.R. (Positive Temperature Coefficiency Resistor) to dry the foamed product.