To obtain a high capacity vacuum soundproof material coping with a broad sound range from a low sound to a high sound, while coping with a strength necessary for a vacuum body such as an atmospheric pressure load by using one side face of an air-tight material as a convex body while using a lightweight, thin, and hard metallic sheet for sound receiving side air-tight material and simplifying the shape by using the same convex body or a plane material with the confronting air-tight material.

A metallic sheet material in which a plurality of slender rectangular convex bodies 3 having a substantially semi-arcuate section, provided with ribs 6 at necessary positions are molded, is used for a sound receiving side air-tight material 2. A diffusing sound side air-tight material 4 is arranged at the bottom face of the sound receiving side air-tight material 2 and the outer peripheral part 5 is air-tightly joined and the inside of the convex body 3 is evacuated.