Abstract: An electrical characteristics evaluation apparatus comprises a terahertz pulse light source that irradiates terahertz pulse light onto a semiconductor material, a light detector that detects pulse light having been transmitted through or having been reflected by the semiconductor material, a measurement device that obtains a spectral transmittance or a spectral reflectance by using a time-series waveform of the electric field intensity of the transmitted pulse light or the reflected pulse light and an arithmetic operation unit that calculates an electrical characteristics parameter of the semiconductor material based upon the spectral transmittance or the spectral reflectance. By adopting this electrical characteristics evaluation apparatus and the corresponding electrical characteristics evaluation method, the electrical material quantities (such as the carrier density, the mobility, the resistivity and the electrical conductivity) of the measurement target, i.e.