To efficiently convert the vibration of a thermal engine into electric energy.

A power generator 100 is attached to an internal combustion engine 1, and has a power generating means 10 for converting a reciprocating motion into the electric energy. An input shaft 12 of the power generating means 10 is attached to the internal combustion engine 1 through a bracket 8. The vibration of the internal combustion engine 1 is input from the bracket 8 to the power generating means 10. The vibration of the internal combustion engine 1 inputted to the power generating means 10 is directly converted into the electric energy by the power generating means 10.