This paper develops a numerical model to examine the performance of the vibration energy harvester with one-rod (unimorph) of Iron-Gallium (Galfenol). The device's principle of operation is based on inverse magnetostrictive effect of the Galfenol rod. In order to take into consideration the anisotropy of the Galfenol, the Armstrong model is employed that is implemented into a static 3-D finite element model (FEM) of the energy harvester. The predicted results from the numerical model are compared to the measured ones.