The present inventors examined the inhibitory activity against HCV replicon of myriocin, fumonisin B1, and ceramide trafficking inhibitor HPA-12, which are compounds derived from microorganisms such as those of the genus Aureobasidium, and found that these compounds have the effect of inhibiting the replication of HCV replicon RNAs or inhibiting the expression of HCV proteins. The present inventors further performed serine palmitoyltransferase knockdown experiments using siRNAs, and results showed that HCV replicon activity and HCV protein expression were significantly inhibited in cells with suppressed LCB1 expression. Thus, sphingolipid biosynthesis was found to be involved in HCV infection. This showed that HCV infection can be treated or prevented by inhibiting enzyme activities involved in the process of sphingolipid biosynthesis by adding compounds or knocking down a gene.