When overhead earth wires are partially insulated, electrostatically induced power can be drawn from power lines by the capacitance between the power lines and the insulated overhead ground wires (I GW). Obstruction light that uses electrical power obtained in this way as their power source are called electrostatic induction method obstruction light. In the electrostatic induction method, insulating the overhead ground wires makes it easy to extract electrical power, making it possible to install obstruction light in locations where it would be difficult to lay power lines, such as riverbeds and mountainous regions. Also, since the electrostatic induction method does not involve any connection to power lines, it is a safe method that does not allow general users to be affected by irregular voltage resulting from lightning strikes on towers, etc. Using power electrostatically induced from power lines to light obstruction light is extremely effective in saving energy, reducing installation costs and providing long life lighting.