An electric heating device includes a main tube which includes multiple heating areas. Each heating area has a hating bar received therein to provide thermal energy to the liquid passing through the heating areas and to increase the temperature of the liquid. A control unit has multiple control members and each control member is electrically connected to and controls one of the heating bars. Each of the control members has a heat dissipating tube connected thereto. The multiple heating areas are cooperated respective heating bars to increase the contact areas between the liquid and the heating bars to quickly increase the temperature of the liquid.