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, wherein the metal layer of the upper envelope and the metal layer of the lower envelope being opposite to each other, wherein at an area facing the internal structure in an end of the envelope, the upper envelope and the lower envelope are adhered by a heat adhesion part, and at an area opposite to the internal structure in the end of the envelope, the upper envelope and the lower envelope are adhered by polyurethane.