Abstract: A method of measuring the temperature of a matter accurately, in non-contact fashion and without setting any emissivity comprising obtaining a spectral characteristics of absorbing electromagnetic waves inherent to a matter whose temperature is to be measured, obtaining those absorption peak wavelengths of the electromagnetic waves which correspond to two or more high points of electromagnetic wave absorption rate obtained from the spectral characteristics, measuring amounts of the electromagnetic waves, which have the absorption peak wavelengths, radiated from the temperature-measured matter, and calculating the temperature of the matter from blues of the radiant amounts of the electromagnetic waves thus measured.