To achieve the production of a thermostable DNA polymerase free from bacterial DNA contamination, we developed eukaryote-made thermostable DNA (Taq) polymerase. The novel eukaryote-made thermostable DNA polymerase resolves the problem of contaminating bacterial DNA in conventional bacterially made thermostable DNA polymerase as a result of its manufacture and incomplete purification. Using eukaryote-made thermostable DNA polymerase, the sensitive and reliable detection of bacteria becomes feasible for large fields, thereby making the development of a wide range of powerful applications possible.