The final goal of this study is to develop a multi-purpose measurement system, which can simultaneously obtain thermal conductivity, total hemispherical emittance, thermal expansion, thermal diffusivity, and specific heat, by a direct electrical heating method. In this report, the principle of the newly developed method in measuring thermal diffusivity is described. Rod samples of silver (purity 99.99%) and JIS SUS304 austenitic stainless steel of 200 mm in length and 1.494 mm in radius are used in order to verify the applicability of this method. Theoretical evaluation of measurement error in this measurement is also conducted. From the experimental results and their evaluation, it becomes clear that this method is satisfactory for precisely determining the thermal diffusivity of a rod sample.