We expect that energy harvesting system by a wind become small power sources for sensors. In this study, we are developing a compact power generator, converting a wind flow energy into an electric energy, with a simple structure utilizing self-excited vibration (galloping phenomena). This paper describes experimental investigations of the power generators at laboratory experiments and outdoor experiments. According to the experimental results, the effects of difference of bluff bodies are shown and the power generator can generates power electricity 0.3 mW at wind velocity 3 m/s.