A dishwasher in one embodiment is provided with a spray arm, and the spray arm is provided individually with areas configured to spray water to a first spray area and a second spray area, and sprays water to the first spray area to entirely wash objects to be washed accommodated in the dishwasher and sprays water to the second spray area to wash objects to be washed with remaining contaminants by applying a great impact on the object to be washed with remaining contaminants.