An opaque silica glass article comprising a transparent portion and an opaque portion, wherein the opaque portion has an apparent density of 1.70-2.15 g/cm3 and contains 5null104-5null106 bubbles per cm3, said bubbles having an average diameter of 10-100 nullm; and the transparent portion has an apparent density of 2.19-2.21 g/cm3 and the amount of bubbles having a diameter of at least 100 nullm in the transparent portion is not more than 1null103 per cm3. The opaque silica glass article is made by a process wherein a mold is charged with a raw material for forming the opaque portion, which is a mixture comprising a silica powder with a small amount of a silicon nitride powder, and a raw material for forming the transparent portion so that the two raw materials are located in the positions corresponding to the opaque and the transparent portions, respectively, of the silica glass article to be produced; and the raw materials are heated in vacuo to be thereby vitrified.