Abstract: An electric heating unit comprises a heat-insulating main body consisting primarily of a heat-insulating material and formed with a groove in a surface thereof, and a heating element provided in the groove and shaped in the form of waves with an amplitude greater than the width of the groove, the heating element having at widthwise opposite sides thereof bent portions extending into the main body from groove-defining opposite side walls thereof and thereby integrally supported by the main body. A bottom-forming member of refractory material made separately from the main body covers the bottom of the groove and is supported by the main body integrally therewith so that the surface of the member toward the opening of the groove is exposed from the main body. The heating element is disposed closer to the groove opening than the bottom-forming member and integrally supported by the main body so as to be in contact with portions of the surface of the member.