The resistivity of a transparent conductive film is determined with high accuracy nondestructively, contactlessly, and efficiently. A resistivity checking device includes an illuminating device (3) for illuminating the transparent conductive film formed on a translucent substrate being conveyed in a manufacturing line from the transparent conductive film side with a P-polarized illuminating light having a wavelength selected by a check condition selecting method at an angle of incidence selected by the method, a photodetecting device (2) for detecting light reflected from the transparent conductive film, and an information processing device (7) for calculating the evaluation value concerning the intensity of the reflected light of the wavelength from the intensity of the detected light and determining the resistivity from the evaluation value by using the correlation characteristic such that the evaluation values and the resistivities are associated with one another.