An embodiment of the present invention is directed to a pyrolysis device including a reactor in which an injected raw material and a melted liquid metal are present together, a circulating pump connected to the reactor, a buffer tank disposed on an upper portion of the reactor and receiving the liquid metal from the circulating pump, a nozzle coupled with the buffer tank and jetting the liquid metal within the buffer tank into the reactor, a separating apparatus separating pyrolyzed char and slag, and a combustion furnace connected to the reactor to combust the fuel supplied from the reactor and supply heat to the reactor, thereby reacting the liquid metal sprays jetted from the nozzle with gases generated in the reactor to purify the gases.