An electric steam iron includes a housing, a water tank within the housing, a bottom plate to which the housing is secured, a heating device in the bottom plate for heating the bottom plate, a boiling chamber inside the bottom plate, and a further independent steam boiler above the bottom plate, and having an inlet in fluid communication with the water tank and an outlet in fluid communication with the inlet of the boiling chamber, such that steam from the steam boiler will be supplied to the boiling chamber in the bottom plate and further heated by the high temperature of the bottom plate, so that little drops in the steam will be fully boiled, thereby providing a high purity of the steam sprayed out of the bottom plate.