Provided is a low thermal expansion super-heat-resistant alloy which has low thermal expansion, high strength, good oxidation resistance and good creep rupture ductility, while being suitable for large-size components by being free from the occurrence of macrosegregation. A low thermal expansion super-heat-resistant alloy which is composed of, in mass%, 0.1% or less of C, 0.1-1.0% of Si, 1.0% or less of Mn, 25-32% of Ni, more than 18% but less than 24% of Co, more than 0.25% but 1.0% or less of Al, 0.5-1.5% of Ti, more than 2.1% but less than 3.0% of Nb, 0.001-0.01% of B and 0.0005-0.01% of Mg, with the balance being made up of Fe and unavoidable impurities, while satisfying Mg/S ≥ 1, 52.9 ≤ 1.235Ni + Co < 55.8%, (Al + Ti + Nb) is 3.5-5.5%, and the F value is 8% or less. This low thermal expansion super-heat-resistant alloy has a structure wherein a particulate intermetallic compound, which contains one or more elements selected from among Si, Nb and Ni in an amount of 36% by mass or more, is precipitated
