The present disclosure relates to a clothing treatment device capable of omitting a frame for structurally connecting an inner case and a cabinet by filling a foaming agent between the inner case and the cabinet forming an appearance. The clothing treatment device comprises a cabinet having an opening at the front thereof: a door which is rotatably provided in front of the opening to open and close the opening; an inner case which is provided in the cabinet to form an accommodation space in which clothes are accommodated, and a hot air supply unit which is provided at the lower portion of the inner case to supply at least one of hot air and moisture to the accommodation space, wherein the inner case is formed of a styrene resin that maintains adhesion to the foaming agent injected into the inner portion of the cabinet.