Abstract: High-temperature apparatus (10) for converting an starting material (M) to a synthesis gas (G) and comprising a feeding device (30) and a rotationally symmetrical furnace pipe (20) having a rotation axis (R). The feeding device (30) conducts the starting material (M) into an inner chamber (I) of the furnace pipe (20), and conveying elements (22) are arranged in the inner chamber (I) of the furnace pipe (20) in order to convey the starting material (M) in the direction of an exit side (A) of the furnace pipe (20). The apparatus (10) comprises an elongate resistance heating (23), which protrudes into the interior (I) of the furnace pipe (20) and which comprises at least one hot zone (H1) and a less hot zone (H2), wherein the hot zone (H1) follows the less hot zone (H2) as viewed from the entry zone (E), and wherein the resistance heating (23) is configured such that a temperature that is above 1200° C., is achievable in the inner chamber (I) of the furnace pipe (20).