<PICT:1048265/C1/1> A high-temperature heating element of silicon carbide having a porous basic structure is provided with a gas-tight covering layer at least 0.01 mm. thick, also of silicon carbide, to increase the oxidation resistance of the element. As shown, a silicon carbide element has a porous region 4, a region 3 where the pore space is sealed with silicon carbide, and a covering layer 2 again of silicon carbide. The element may be of tubular construction (Fig. 3, not shown) or may be of U-shaped bar or plate form. The element is produced by heating the basic porous body in a gas consisting of at least one silicon compound, e.g. halogen-substituted silanes, and at least one carbon compound, e.g. hydrocarbons, halogenated hydrocarbons, or furfuryl compounds, and/or of at least one organosilicon compound, e.g. alkylsilanes or halogenated alkylsilanes, under a pressure of 0.1 to 10 atmospheres at temperatures above 1200 DEG C. The concentration and/or the temperature of the silicon carbide supplying substances may be varied during the process so that coarsely crystalline and finely crystalline particles are alternately deposited for the sealing.