Provided is a pyrimidine nucleoside compound represented by general formula (1) [wherein A1 and A2 may be the same as or different from each other and independently represent a hydrogen atom, an alkyloxycarbonyl group which may have a substituent, a cycloalkyloxycarbonyl group which may have a substituent, an aryloxycarbonyl group which may have a substituent, or an aralkyloxycarbonyl group which may have a substituent] or a salt thereof.本發明係提供一種由下列通式(1)所表示的嘧啶核苷化合物或其鹽:[式中,A1、A2係相同或相異,表示氫原子、亦可具有取代基的烷氧基羰基、亦可具有取代基的環烷氧基羰基、亦可具有取代基的芳氧基羰基或亦可具有取代基的芳烷氧基羰基]。
