In the case of a heating device (1a) particularly suitable as a continuous flow heater, on an outer surface (4a) of a wall (3a), a tubular heater (6a) and a heat conducting element (10a) are so closely arranged in juxtaposed portions (14a) that the heat conducting element (10a) with a flat side (12a) and the heating element (6a) with a contact surface (16a) are uninterruptedly connected to said surface (4a) by means of very thin layers of a solder-like fixing material (11a). The longitudinal edge faces (21) of the strip-like heat conducting element (10a) are substantially connected to adjacent portions (14a) of the heating element (6a) and by means of solder-like fixing material are connected uninterruptedly to said heating element (6a). The heat conducting element (10a) flanking on either side the portion (14a) of the heating element (6a) with the fixing material (11a), together with the latter and the wall (3a) brings about a substantial homogenization of the distribution of the thermal energy emanating from the heating element portions (14a) on the facing surface (5a) of the wall (3a) used for heating a medium.