To provide a lightning protection device equipped with an umbrella-type electric charge diffuser capable of preventing the damage of diffusion wires.

Provided is a lightning protection device in which an electric charge diffuser 10A is grounded to the ground surface via a grounding conductor 4. The electric charge diffuser 10A comprises: a plurality of arms 12 extending in an umbrella shape from the tip of a metal column erected on the ground surface or a building; diffusion wires 13 spirally arranged so as to traverse each of the arms 12; and wires 14 provided between the adjacent arms 12 and arranged to traverse the diffusion wires 13.