An apparatus for converting vibration energy into electric power is provided, in which vibration of a power source is transmitted to a power-generating coil 14, and is then transmitted to an iron core 20 via helical compression springs 26 and 28, thereby causing relative movement between the iron core 20 and the power-generating coil 14 due to inertia, resulting in a change in the magnetic field. An electromotive force is thus generated due to electromagnetic induction, thereby causing a current to flow to an electric wire material 18. Specifically, use of vibration of the power source as energy for power generation can achieve efficient use of energy. The acquisition of electric energy by the power generation may also lead to mitigation of the vibration.