Vibration based energy harvesting technology is utilized effectively in automobile and infrastructure. For example, thousands of sensors are used in car; however, all of them are essentially powered by battery via power cable. The energy harvesting technology contributes on realization of wireless sensor system without power cable. We have developed novel vibrational power generator using Galfenol, iron-based magnetostrictive material. The generator is based on parallel beam structure consisting of Galfenol plate wound with coil and yoke attached with bias magnet. When bending force is applied on the tip with the other end fixed like cantilever, the magnetization inside the plate varies with induced stress due to the inverse magnetostrictive effect. In vibration, the time variation of the magnetization generates voltage on the wound coils. The magnetostrictive power generator is advantageous over conventional such using piezoelectric material in high efficiency and high robustness, and low electrical impedance. The problem in practical application is mismatch of frequencies between its resonance (several hundred Hz) and vibration source (several ten Hz). In this paper, we propose frequency up conversion mechanism to occur free vibration of the generator by low frequency. The converter, cantilever with magnet, is simple easily combined with the generator. The prototype device using Galfenol plate, 2x0.5x22 mm^3, was evaluated the performance. We verified the maximum power of 1.3 mW at vibration of 103 Hz, 10 G, and the frequency bandwidth is broaden by shape of the magnet.