Provided are: a DNA polymerase mutant having reverse transcriptase activity, the DNA polymerase mutant including a sequence consisting of twelve specific amino acids A1-A12, wherein the DNA polymerase mutant having reverse transcriptase activity is characterized in that the A3 and/or A10 amino acid is substituted by a basic amino acid residue different from that prior to the introduction of mutation; a kit and a composition including the DNA polymerase; a method for producing the DNA polymerase; and a method for modifying an existing DNA polymerase having reverse transcriptase activity.