A method for detecting a mutation in an amino acid at position 93 of a hepatitis C virus NS5A protein, the method including: synthesizing cDNA using, as a template, hepatitis C virus RNA in a sample; and performing a real-time PCR with a cycling probe method using, as a template, the cDNA; wherein a primer set used in the real-time PCR is a certain primer set; and wherein probes used in the real-time PCR include certain probes.