An intensity spectrum designing unit of a data generating device includes an initial value setting unit that sets a plurality of objects of a first generation of an intensity spectrum function A(ω) and a phase spectrum function Ψ(ω), an evaluation value calculating unit that calculates an evaluation value for each of a plurality of objects of an n-th generation, an object selecting unit that selects two or more objects used for generating a plurality of objects of an (n+1)-th generation among objects of the n-th generation on the basis of superiority of the evaluation value, and a next-generation generating unit that generates a plurality of objects of the (n+1)-th generation on the basis of the selected two or more objects. The evaluation value calculating unit, the object selecting unit, and the next-generation generating unit repeat processes while 1 is added to n until a predetermined condition is satisfied.