Recently, novel energy generation systems utilizing hydrogen or organic gases such as a fuel cell are widely investigated. In order to achieve them in practical use and to increase their applicability and safety, a development of gas sensors which are able to detect flammable gases with high response and accuracy is necessary. In this study, titania thin films which were co-loading platinum and palladium fine particles were prepared by wet chemical processes. This thin film showed the change of electro conductivity with high responsibility and concentration dependence against air-diluted hydrogen gas of less than 20%.