Power generation device and power generation system

This power generation device 100, which is used fixed to a vibrating body, is provided with: a first magnet 31; a power generation unit 10 which comprises a coil 40 which is spaced away from and surrounds the outer periphery of the first magnet 31, and springs (60U, 60L) which, relative to the coil 40, displace the first magnet along the magnetization direction thereof; and a second magnet 910 which, when the power generation device 100 is fixed to the vibrating body and this is in a resting state, is arranged at or near the position of the first magnet 31 in a natural state, in which no external force is applied to the power generation unit 10, so as to bring a repulsive force to bear on the first magnet 31 so as to hold the first magnet 31.