The present invention relates to a steam generator (100) and a washing machine therewith. The present invention provides a steam generator (100) including a water chamber (W) for holding water, the water chamber having a heater (200) mounted thereto for heating the water, a steam chamber (S) for holding steam generated as the water is heated, a water supply hose (25) for supplying the water to the water chamber, and a steam hose (53) for discharging steam from the steam chamber, wherein the water chamber has a vertical direction length (a vertical length) relatively greater than its horizontal direction length (a horizontal length).