A dryer is disclosed. The dryer comprises: a body having a first opening disposed at one side thereof; a first drum rotatably disposed in the body and including a first drying chamber connected to the first opening; a first hot-air unit for supplying hot air to the inside of the first drum; a first door coupled to the body to open or close the first opening; a second drum disposed at the first door; and a second hot-air unit for supplying hot air to the inside of the second drum.