A vacuum heat insulating material including a core material and a sheath for covering the core material, the interior thereof being sealed to maintain a reduced pressure therein, wherein the sheath includes a gas-barrier laminate that has at least a heat-melt-adhesion layer, a vapor-deposited layer and a gas-barrier material, and the gas-barrier material has a gas-barrier layer that includes a polycarboxylic acid type polymer and contains a monovalent metal element in an amount of not more than 1.4% by weight, a polyvalent metal element in an amount of at least not less than 5.0% by weight, and a nitrogen element in an amount of 0.01 to 3.0% by weight per the total weight of nitrogen and carbon. The vacuum heat insulating material has excellent heat insulating capability and gas-barrier property, and sustains excellent heat insulating capability over extended periods of time as well as excellent flexibility and waterproof property.