An image generation device includes an imaging unit 11, a projection unit 22, and a distance information generation unit 18, and a projection pattern includes unit patterns arranged in a plurality of rows in a first direction and in a plurality of columns in a second direction. A plurality of light dots include first dots and second dots which are light dots of different states from each other; the unit patterns arranged in the first direction have the light dot arrangements identical with each other; the unit patterns arranged in the second direction have light dot arrangements different from each other; the number of first dots among a plurality of light dots arranged in the first direction in each of the unit patterns is the same fixed number in each row in the second direction; and in a location other than the unit pattern, the number of first dots included in a row of the same length as the unit pattern in the second direction differs from the fixed number, in a certain row in the second direction.