To shorten time to execute an earthing device, and to reduce its execution cost.

An earth unit Eu having an earth wire 1 coated with a conductive coated body 2, and a conductive coating member 3 composed of a carbon powder particle body 3a to surround the periphery of the conductive coated body and a wrapping body 3b to wrap the carbon powder particle body is structured as one unit (piece) having a prescribed length, and the earthing device E is composed of at least one earth unit or more units. The earth unit is formed as one unit (piece) having a prescribed length, and since the earthing device is formed by disposing one or more earth units, the earthing device having a prescribed length can be structured by carrying the required number of earth units into a work execution site and by connecting the earth units each other.