The vacuum insulator includes an internal structure; a filler for filling empty spaces of the internal structure; and an envelope having an upper envelope composed of a metal layer and a polymer layer formed on the metal layer to surround an upper surface of the internal structure, and a lower envelope composed of a metal layer and a polymer layer formed on the metal layer to surround a lower surface of the internal structure, the metal layer of the upper envelope and the metal layer of the lower envelope being opposite to each other, wherein in a certain area along outlines of the upper envelope and the lower envelope, the metal layer of the upper envelope and the metal layer of the lower envelope between which a film composed of a Low density polyethylene LDPE and a Linear-Lowdensity polyethylene LLDPE is inserted, are adhered by heat, and in an area excluding the certain area, the metal layer of the upper envelope and the metal layer of the lower envelope are adhered by polyurethane.