Single phase [Math Processing Error] with [Math Processing Error] of theoretical density was successfully produced by direct hot pressing of elemental powders containing [Math Processing Error] excess Zn for compensating the evaporation during the process. Temperature dependences of thermoelectric properties were investigated from 4 K to 300 K. Seebeck coefficient, electrical conductivity, thermal conductivity as well as thermoelectric figure of merit showed the discontinuity in variation at 242K, indicating the [Math Processing Error] , phase transformation. Interestingly, it was found that lattice thermal conductivity by phonons is dominant in total thermal conductivity of [Math Processing Error] . Therefore, it is expected that thermoelectric properties can be improved by reduction of lattice thermal conductivity inducing lattice scattering centers by doping and solid solution.