The present invention relates to a garment processing apparatus comprising: a hot-air supply unit having a circulation flow path for directing the air drawn out from the interior of a garment receiving unit into the interior of the garment receiving unit, a heat exchange unit provided to the circulation flow path, for condensing and heating the air introduced into the circulation flow path, and a blower for circulating the air in the interior of the garment receiving unit through the circulation flow path; and a dryness detection unit having a flow rate detection means for measuring the amount of condensate water formed in the heat exchange unit, and a control section for determining the amount of moisture contained in the laundry on the basis of the flow rate data provided by the flow rate detection means.