A device for the gasification of liquid or fine-grain solid fuel materials in an entrained bed reactor, at temperatures above the ash melting point and at a pressure of 0.3 to 8 MPa, including a gasification reactor and a water bath being arranged in a pressure vessel. The water bath being installed below the gasification reactor and the a/m gasification reactor being designed in such a manner that the synthesis gas produced is withdrawn in the upper section of the reactor, the liquid slag precipitating on the walls of the reactor chamber and then having a free downflow, without any solidification of the surface of the said slag. The lower side of the reaction chamber has an outlet opening with a drop-off edge so that the downstream of liquid slag can freely fall from the drop-off edge. A slag removal duct is arranged below the opening and reaches down into the water bath, the upper wall section of the slag removal duct is penetrated by a cooling agent and the internal side of the duct is completely lined with a temperature-resistant insulating compound. The lower section of the slag removal duct which reaches down into the water bath is wetted by a water film on the internal side, the upper and lower sections being connected with each other in such a manner that the water film of the upper wall section does not come into contact with the wall section penetrated by a cooling agent nor with the insulating compound.