A washing device is disclosed, which is capable of preventing damage of a substrate caused by drooping of the substrate. The washing device includes a plasma irradiating part supplied with a substrate from a substrate loading part to remove dirt from the substrate by irradiating plasma to the substrate; a dirt washing part supplied from the substrate from the plasma irradiating part to remove dirt remaining on the substrate; a finishing washing part supplied with the substrate from the dirt washing part to wash the substrate; a drying part supplied with the substrate from the finishing washing part to dry the substrate; and a substrate unloading part supplied with the substrate from the drying part to unload the substrate, wherein the plasma irradiating part includes a plasma irradiation unit that irradiates plasma to the substrate and a floating unit that maintains the substrate in a floating state.