Abstract: Some embodiments in the present disclosure provide a cooling apparatus for mold transformers, which may be installed at opposite sides of a lower portion of the mold transformer having a first space formed between a core and a low voltage coil and a second space formed between the low voltage coil and a high voltage coil, characterized in that the cooling apparatus comprises a duct extending from the cooling apparatus in a direction toward the mold transformer, a discharge port of the cooling apparatus is configured to direct toward lower ends of the low voltage coil and the high voltage coil, so that cooling air discharged from the duct is injected into the inside of the first and second spaces.