In this paper, an equivalent elastic modulus of unsymmetrical hexagonal honeycomb is studied by using numerical results of FEM. The force is applied in such a direction parallel to one of the cell walls. A rotation of a unit around the joint point of three cell walls is necessary to simulate a deformation of honeycomb exactly, because of anisotropy of the unsymmetrical honeycomb. The deformation of honeycomb consists of two kinds of deformations: one is a deformation inside the unit, which is caused by the bending, stretching and shearing of cell walls and the rigid rotation of inside unit, and the other is relative displacement among units. The equivalent elastic modulus is determined from the relative deformation among units Also, the accuracy of the equivalent elastic modulus obtained in this method is found to be very high in comparison with the numerical results because of considering bending, stretching and shearing deformation of cell walls.