To provide a quartz glass furnace core tube for low pressure CVD in which height dimension nearly equal to that of a furnace core tube formed of metal material can be obtained although the furnace core tube is formed of quartz glass and high strength is realized.

In this quartz glass furnace core tube for low pressure CVD, a ceiling part 4 having a domed shape whose radius is R1 is combined with a cylindrical part 3 whose radius is R by a combining arc part 5 whose radius is R2. The quartz glass furnace core tube has a shape wherein R1=1.6R-2.4R and R2=0.2R-0.4R and is used at an internal furnace temperature of at most 900°C, and compression residual stress is made to exist on an outside surface layer of the combining arc part.