Having a base sequence complementary to the base sequence or a nucleotide sequence comprising the nucleotide of interest to the mutated site and a nucleotide sequence containing a mutation site on the target nucleic acid, fluorescent material, 3 end terminal 5 a detection probe consisting of an oligonucleotide quencher is added to, the introduced modifications such as higher than 3 ℃ than the melting temperature of the counter probe melting temperature of the probe Furthermore, Probe set comprising, a counter probe consisting of an oligonucleotide having a nucleotide sequence complementary to the base sequence or a nucleotide sequence comprising a nucleotide different from the bases of the target in the mutated site a nucleotide sequence containing a mutation site performs a real-time fluorescence PCR was used to identify the type of the base in the mutation site of the target nucleic acid.標的核酸上の変異部位を含む塩基配列であって該変異部位に目的の塩基を含む塩基配列、または該塩基配列に相補的な塩基配列を有し、5末端に蛍光物質が、3末端に消光物質が付加され、さらにプローブの融解温度がカウンタープローブの融解温度よりも3℃以上高くなるような修飾が導入されたオリゴヌクレオチドからなる検出用プローブと、変異部位を含む塩基配列であって該変異部位に前記目的の塩基とは異なる塩基を含む塩基配列、または該塩基配列に相補的な塩基配列を有するオリゴヌクレオチドからなるカウンタープローブと、を含むプローブセットを用いて蛍光リアルタイムPCRを行い、標的核酸の変異部位における塩基の種類を特定する。
