Abstract: An object of the present invention is to provide an opaque quartz glass containing pores with irregular shapes and having sufficient heat ray reflecting, heat ray blocking and light shielding properties, and further to provide a method for producing the opaque quartz glass. The opaque quartz glass of the present invention is an opaque quartz glass containing pores with irregular shapes dispersed in a glass body, wherein the opaque quartz glass has a pore size distribution of the pores having D50 of 4 to 30 ?m, a proportion of pores with pore sizes of 5 ?m or less of 1 to 50%, and a proportion of pores with pore sizes of 15 ?m or less of 30 to 90%, and an area ratio of pores in a microscopic image at a cross section of 5% or more. The opaque quartz glass of the present invention is obtained by mixing a plurality of types of the specific silica powders having different particle size distributions from each other at a predetermined formulation, and sintering a pressure-molded article of the mixed powder.