An electric steam generator for generating superheated steam for domestic use includes a cylindrical body provided with a plurality of sector-shaped vaporization chambers closed at their top by a removable plate defining at its central region a first superheating chamber. An inverted cup-shaped body closed at its top by a plate and having a lateral wall defines, together with the removable plate, a second superheating chamber surrounding the first superheating chamber. The body is provided with an electric resistance heater for heating the vaporization and superheating chambers to operating temperature. Water is pumped into the vaporization chambers where it is instantaneously vaporized to steam which flows therefrom in series through the first and second superheating chambers to a steam delivery duct. The vaporization chambers and superheating chambers are connected by ducts of reduced diameter to subject the flowing steam alternately to acceleration in the ducts and to expansion in the chambers thereby assuring complete vaporization of the water and delivery of dry superheated steam.