An electronic device for repelling fish with Lorenzini organs includes (1) a generator having a power supply and output terminals including a first output terminal and a second output terminal, for converting a DC voltage supplied from the power supply to an AC voltage having an amplitude of less than 100V and outputting the AC voltage from the output terminals, (2) at least one electric wire, one or each of which is connected to one or both of the first output terminal and the second output terminal, and (3) a power switch that forms an electric circuit together with the generator and the at least one electric wire to turn on and off the output from the power supply, and that causes the power supply to supply a DC voltage when the first output terminal and the second output terminal are electrically connected via the seawater.