PROBLEM TO BE SOLVED: To provide an illumination device in which in backlight scan, in which a plurality of light emission periods are provided in one frame period, variation in luminance is suppressed when acquiring a sensor value of luminance for each LED block.SOLUTION: One frame period is divided into a plurality of groups, and a PWM duty ratio of a PWM cycle in each group is determined so that a light emission period of a light source in one frame period, which is determined on the basis of a video signal, can be distributed to a plurality of groups at a prescribed ratio. Measurement means for receiving light from a light source of a measuring object for a prescribed measurement period to thereby measure luminance of the light source of the measuring object is provided. During a measurement period, a light source which is not the measuring object is lighted out, and as to a light source whose light-off period for the measurement is set within the light-on period determined on the basis of the prescribed
