Recent developments in the field of vibration-based power generators have highlighted the advantages of using Fe-Ga alloys; these are excellent-magnetostrictive materials having good mechanical properties, which makes them well suited for use as magnetostrictive elements. A rectangular Fe-Ga element oriented along the 100 direction in a U-shaped unimorph device produces a higher power generation efficiency than samples with other orientations such as 110 and 111. The crystal growth direction of the ingots and plane orientation of the elements have a minimal effect on the power-generation efficiency. The observations of the magnetic domain and elastic properties suggest that the anisotropy in power generation is attributable to the anisotropic magnetic and elastic properties of the Fe-Ga alloy. Thus, a high-performance, vibration-based power generator using the Fe-Ga alloy should be fabricated using elements with a 100 orientation, cut from a single-crystal Fe-Ga ingot.