Abstract: A heat-resistant sintered sliding member according to the present invention has a structure in which a lubrication phase is dispersed in a matrix, in which an entire composition of the sliding member is composed of a composition containing, by mass %, Cr: 18% to 35%, Mo: 0.3% to 15%, Ni: 0% to 30%, Si: 0.5% to 6%, S: 0.2% to 4.0%, P: 0% to 1.2%, B: 0% to 0.8%, and a Fe balance containing inevitable impurities, in which the matrix is a Fe—Cr—Mo—Si-based matrix or a Fe—Cr—Mo—Ni—Si-based matrix, the lubrication phase contains chromium sulfide, and a porosity of an entire sliding member is 2.0% or less.