A highly reliable vacuum heat insulating material having excellent processability, usability and heat insulating performance and a heat insulating box using the vacuum heat insulating material are provided. A vacuum heat insulating material related to the present invention includes: a core material structured by a laminated structure of an organic fiber assembly formed by forming an organic fiber into a sheet shape and cutting an end face with a predetermined length, and having a core material opening portion formed by a through hole or a notch with cutting; a gas-barrier outer cover material containing the core material inside, having a sealing portion for sealing surrounding of the sheet-shaped organic fiber assembly and surrounding of the core material opening portion, and hermetically sealing an inside with almost vacuum status by sealing the sealing portion; and an outer cover material opening portion provided at the outer cover material under a status in which the sealing portion provided at the surrounding of the sheet-shaped organic fiber assembly and the surrounding of the core material opening portion is sealed, being a through hole or a notch which is smaller than the core material opening portion with a sealed amount, and a long fiber being equal to or longer than a length of the sheet is used for the organic fiber.