An evaluating method for evaluating an ultraviolet radiation protection effect in a measurement sample includes a first step of measuring a temporal change of the spectral transmission spectrum in the measurement sample within a predetermined wavelength range at predetermined wavelength intervals by irradiating with light including ultraviolet radiation from a light source under a predetermined light irradiating condition, a second step of setting a correlation between a light irradiating time and minimal erythema doses by predetermined time intervals based on the temporal change of the spectral transmission spectrum obtained in the first step, and a third step of calculating a predicted in vitro SPF in the measurement sample using a time until an accumulated minimal erythema dose that is obtained as a time integration of the minimal erythema doses based on the correlation obtained in the second step reaches 1 MED.
