A spectral characteristic measuring system includes, a data processing apparatus, and a program, which correct an illumination light variation caused by a temperature rise in a semiconductor light-emitting element due to light emission or in a scanning type color measurement system, which sequentially measures color samples 1n and in which a semiconductor light-emitting element is used as a light source.Spectral distributions of illumination lights which are measured before and after the color sample is measured are interpolated, to estimate a spectral distribution of an illumination light at the time when a spectral distribution of the color sample is obtained. Spectral characteristics of the color sample are identified based on the spectral distribution of the reflected light or the transmitted light reflected by or transmitted through the color sample and the estimated spectral distribution.