A cooling air passage apparatus of a refrigerator includes: a left cooling air duct installed having a plurality of cooling air discharge holes in the vertical direction at the left side of the opened marginal portion of an inner case forming a storage chamber, and discharging cooling air from the left side of the storage chamber toward a refrigerator door; a right cooling air duct installed having a plurality of cooling air discharge holes in the vertical direction at the right side of the opened marginal portion of the inner case, and discharging cooling air from the right side of the storage chamber toward the refrigerator door; a ventilating unit for ventilating cooling air generated from a freezing system to the storage chamber; and a diverging unit for diverging and guiding cooling air ventilated by the ventilating unit to the left cooling air duct and the right cooling air duct.