Provided is a vacuum thermal insulation material which is capable of maintaining a vacuum for a long period of time in a high temperature range. The present invention relates to a vacuum thermal insulation material which comprises a core material and an envelope in which the core material is sealed. The envelope comprises thermal fusion bonding layers, and the thermal fusion bonding layers that face each other at an end portion of the envelope are thermally fused to each other, thereby forming a sealed portion. The core material has a first main flat surface that is exposed to the relatively high temperature side when in use and a second main flat surface that faces the first main flat surface and is exposed to the relatively low temperature side when in use. At least a part of the sealed portion is arranged on the second main flat surface side.