A structure of a brake-cooling duct, which is disposed at one side of an intercooler tank to cool a brake disc using air may include the brake-cooling duct has an air movement channel and a through-hole formed in a side surface thereof to expose the channel to an outside, wherein the brake-cooling duct is disposed close to one side of the intercooler tank so that an external surface of the intercooler tank is exposed to the channel via the through-hole, allowing the air introduced into the channel to be brought into contact with the external surface of the intercooler tank, and thereafter be discharged rearward thereof.