Micropolar theory, one of the generalized continuum mechanics theories, is characterized by rotational degrees of freedom φ, which are independent from displacepent u. In this study, we apply micropolar theory to deformation analysis of a elastic body which has internal structures. The micropolar model and the classical model considering internal structures explicitly is simulated to examine the appropriateness of the micropolar model. Relationship of characteristic length, the new elastic constant introduced micropolar theory, and the scale of internal structures is illustrated.