To provide a black synthetic quartz glass with a transparent layer, which has high emissivity in the far infrared region, has excellent light-shielding properties, maintains the same degree of purity as synthetic quartz glass in terms of metal impurities, has high-temperature viscosity characteristics comparable to natural quartz glass, can undergo high-temperature processing like welding, and does not release carbon from its surface; together with a method for the production thereof.A porous silica glass body containing hydroxyl groups is subjected to a gas phase reaction in a volatile organosilicon compound atmosphere at a temperature between 100° C. and 1200° C. and, following the reaction, evacuation is commenced and, on reaching a degree of vacuum exceeding 10 mmHg (1343 Pa), heating is carried out at a temperature between 1200° C. and 2000° C. to produce a compact glass body.