The present disclosure includes a reinforcing fiber of 34 ~ 59.9% by weight of silica, 39 ~ 57% by weight of the inorganic powder and 1-7% by weight, wherein the inorganic powder is SiO ₂ content of more than 93%, Al ₂ O ₃ content It includes not more than 2% diatomaceous earth vacuum insulation panel core, and the shell material surrounding the core, and the core material for the vacuum heat insulating material made of for, to a vacuum heat insulating material is formed inside the pressure-sealing the outer skin material. In addition, the present disclosure is to form a mixture by mixing the reinforcing fiber of 34 ~ 59.9% by weight of silica, 39 ~ 57% by weight of the inorganic powder and 1-7% by weight; And a step of compression molding the mixture, wherein the inorganic powder is a SiO ₂ content is more than 93%, Al ₂ O ₃ Method vacuum manufacture of the insulation core material for characterized in that the content is composed of more than diatomite 2% and the preparing a core material for vacuum insulation materials; Phase surrounding the core material to the shell material; And to a method of producing a vacuum insulation material comprising the step of sealing pressure to the inside of the outer skin material. According to an aspect of the invention, maintaining a low thermal conductivity properties of the vacuum heat insulator, while ensuring a high heat insulating performance can remarkably reduce the manufacturing cost, and manufacturing to exert the excellent effects in handleability and workability side during the production of the core material It can improve the efficiency of the process.