The periodic inspection of a bridge requires visual observation and hammering, which is very costly. In addition, the inspection is sometimes difficult, depending on the place of installation. Consequently, there is a need for remote health monitoring of structures using wireless modules. However, nowadays, these monitoring systems use batteries for power supply and need periodic battery replacement. As a solution, we investigate vibration generators using magnetostrictive materials (Fe-Ga alloy) as a power source for remote health monitoring. Using this system, we can inspect infrastructures without maintenance such as changing batteries. The generator features a simple structure, robustness, and high output and is close to practical application. In this paper, we propose an extra-large magnetostrictive vibration power generator that can generate practical power using a low frequency (10~20 Hz), such as bridge vibration. It is 300 mm in length, 5 kg in weight, and uses a Fe-Ga alloy plate with dimensions of 40 × 4 × 125 mm3 . First, we improve the output of the generator by adding a reinforcing plate and adjusting the bias magnetic field. Next, we confirmed the generation of an instantaneous maximum power of 0.58 W and effective power of 0.22 W under sinusoidal vibration (18.5 Hz, 0.2 G). Furthermore, we reproduced bridge vibration and evaluated the characteristics of the extra-large generator. Finally, we confirmed that 88 mJ of energy was stored in the storage capacitor from reproduced vibration of the bridge in 5 s.