Provided with: a detecting means to detect a possible light intensity changing frequency of a measuring object; a frequency determining means to determine a light intensity changing frequency with reference to the possible light intensity changing frequency; a resolution determining means to determine a frequency resolution for flicker measuring with reference to the determined light intensity changing frequency; and a flicker measuring means to conduct flicker measuring with the determined frequency resolution. The resolution determining means determines the frequency resolution to be an integral submultiple of the light intensity changing frequency determined by the frequency determining means.