An apparatus for treating clothes and a method for controlling the same, which are capable of controlling or preventing formation of creases on clothes, are disclosed. The disclosed apparatus includes a drum (20), a steam generator (200) to supply steam to the drum (20), a water container (300) to store water to be supplied to the steam generator (200), the water container (300) detachable, a sensor (500) to sense whether the water container (300) is detached or attached, a water supplier (400) to supply the water stored in the water container (300) to the steam generator (200), and a controller to control an operation of the water supplier (400) based on a sensing result of the sensor (500).