Alumina sintered body and method for producing the same

An alumina sintered body having communicating pores of 400-1100 Å in average pore diameter and 4-16% in porosity and being obtainable by mixing first alumina particles 1 having a particle diameter of 0.2-0.7 mum and a sphericity of 0.7-1.0 as an aggregate and second alumina particles having a particle diameter of 0.01-0.1 mum as a pore forming material to embed a plurality of the second alumina particles 2 in the spaces between the first alumina particles 1 , and sintering the mixture at a temperature of 1200-1400° C. The alumina sintered body can be used for a part for various gas permeable industrial materials inclusive of protective film for gas sensors, and the like.