A dishwasher comprising: a first body; and a second body which includes a rack to hold an object to be washed, a spray nozzle to spray water onto the object, and a washing channel connectable to the spray nozzle, where the second body is coupleable to or coupleable from a top surface of the first body. The first body includes a washing pump to supply water, a supply channel to supply the water to the washing channel, a drain port to receive the water from the second body, and an upper housing which is coupleable to an opening formed at an upper surface of an external support such that so that while the upper housing is coupled to the opening the first body is positioned at a lower end of the upper surface of the external support.