A sensor device includes: a light sensor that acquires a first light quantity measurement value that is proportional to a light quantity of a backlight and a first measurement time; a light quantity target value calculating unit that calculates a light quantity target value based on a user setting for the backlight; and a measurement time calculating unit that calculates a second measurement time for when the light sensor acquires a second light quantity measurement value a next time, based on the acquired first light quantity measurement value and the light quantity target value.