The invention relates to an oil-water separating device and an oil sludge separating apparatus including the same. The oil-water separating device comprises a shell, an oil feeding unit arranged on the shell, a drainage hole, an oil outlet and a heat exchange unit arranged in the shell, wherein the heat exchange unit comprises multiple layers of heat exchange tubes, the oil feeding unit comprises an oil feeding pipeline communicated with the interior of the shell, the end , located in the shell, of the oil feeding pipeline is provided with a plurality of nozzles, and the nozzles are located among the heat exchange tubes or below the heat exchange tubes. The oil-water separating device provided by the invention has good condensation effect, can effectively reduce the temperature of high-temperature oil gas, greatly improves oil-water separation efficiency, enhances the utilization rate of waste oil, and achieves the purposes of energy conservation and environmental protection.