A DNA polymerase in which a mutation is induced at a specific amino acid position to increase gene mutation specificity, a nucleic acid sequence encoding the polymerase, a vector comprising the nucleic acid sequence, and a host cell transformed with the vector are disclosed. Provided are a method for in vitro detecting one or more gene mutations or SNPs in one or more templates by using a DNA polymerase having increased gene mutation specificity, a composition for detecting a gene mutation or SNP comprising the DNA polymerase, and a PCR kit comprising said composition. Furthermore, provided are a PCR buffer composition for increasing the activity of a DNA polymerase having increased gene mutation specificity and a PCR kit for detecting a gene mutation or SNP comprising the PCR buffer composition and/or the DNA polymerase having increased gene mutation specificity.