A numerical model related to fluttering of an insect, when an equivalent model of actual structure of a wing of the insect is moved in the air in accordance with a model of fluttering motion of the wing of the insect is calculated by fluid-structure interactive analysis, in which behavior of the wing and behavior of the air are given as numerical values, including interaction therebetween. Thereafter, a method of controlling a fluttering robot, wing shape and the like are determined by modifying numerical models of fluttering of an insect prepared by fluid-structure interactive analysis, in accordance with sensitivity analysis. Accordingly, a method of preparing numerical models of wing and air considering the behavior of the wing of the insect in the air is provided and, in addition, a method of manufacturing a fluttering robot utilizing the numerical model prepared by this method of preparing numerical model can be provided.