A drying system is provided to prevent environmental contamination by precluding cleaning agent when removing lubrication oil after machining a case. A drying system comprises a drying room(2) in which a space is prepared inside; a transfer part(10) on which a piece of work rests and which carries it; a first air part(20) spraying air in order to allow oil of a piece of work to be diffused uniformly, located on one side of the transfer part; a second air part(30) spraying air to the edge direction in order to remove the oil collected in the edge of a piece of work; a blowing part(40) allowing air circulation to occur inside the drying chamber; and a heating part(50) drying a piece of work by generating hot blast.
