An earthing device which needs not be buried under the ground is provided. The earthing device includes an earthing panel and a discharging device mounted inside the earthing panel. The discharging device includes at least one electrode plate, multiple discharging electrodes coupled to the electrode plate, and catalyst filled between the discharging electrodes. Since an earth electrode needs not be buried under the ground, it requires less construction costs, time and area, and environmental pollution (especially, soil pollution) does not happen. Further, the earthing device can be simply and economically installed regardless of place.