A dishwasher is a type in which a part of wash water contained in a wash water tank is replaced with rinse water every washing cycle. The dishwasher determines whether a present washing cycle is in timing of executing a detergent increase supply processing or in timing of executing a detergent normal supply processing (S304). Based on this determination result, by the execution of the detergent increase supply processing, a supply amount of the detergent is increased (S309). Consequently, in the dishwasher, the detergent concentration in the wash water is properly adjusted.