To provide a high zirconia fused cast refractory having high durability, which hardly has cracks at the time of production of the refractory, during the heating, by temperature changes during use and during the cooling at the time of suspension of operation. A high zirconia fused cast refractory which has a chemical composition comprising from 88 to 96.5 mass % of ZrO2, from 2.5 to 9.0 mass % of SiO2, from 0.4 to 1.5 mass % of Al2O3, from 0.07 to 0.26 mass % of Na2O, from 0.3 to 1.3 mass % of K2O, from 0 to 0.3 mass % by outer percentage of Li2O, at most 0.08 mass % by outer percentage of B2O3, and at most 0.08 mass % by outer percentage of P2O5, and contains B2O3+P2O5 in a content of at most 0.1 mass % by outer percentage.