A device for the electrical heating of a liquid with high thermal flow, according to which the resistor in tubular form and supplied with direct current can indirectly heat the liquid by conduction through an electrically insulating and thermally conductive intermediate element that surrounds it with direct mechanical contact, the assembly consisting of tubular resistor and intermediate element being jacketed by a sheath intended to be immersed, over at least a major part of the length thereof, in the liquid to be heated. The preferred application is the electrical simulation of nuclear fuel rods intended to be assembled in power reactors, of the PWR but also RNR-Na type.