A transformer cooling apparatus is provided in which the internal temperature of the transformer can be made uniform without requiring an auxiliary fan or the like, and the size of the transformer disk can be reduced, the cost can be reduced, and the assembling work can be facilitated. The transformer cooling apparatus comprises an upper divider plate (4) and a lower divider plate (5) respectively disposed at two axial ends of winding portions (3R, 3S, 3T), and an exhaust fan (21) is arranged near the upper portion of a frame body (1); air inlets (22-24) are formed; first (S1) second airflow (S2) are formed by the operation of the exhaust fan (21); through the cooling air flowing from the air inlet (22) to the periphery of the winding portion goes through the direction of the exhaust fan (21)through the end air port (4c) between the inner surface of the frame body (1) and the end portion of the upper partition plate (4) to form the first airflow (S1); the cooling air flowing in from the air inlet (23, 24) passes through in the direction of the exhaust fan (21) along the axial direction of the winding part via the vent holes (4a, 5a) inside the partition plate and the inside of the winding part to form the second airflow (S2).