To provide a simple heat exhaust structure of an engine compartment, which requires only a small space for installation in the engine compartment and a front fender, and which can discharge hot air in the engine compartment to the outside.

The heat exhaust structure includes an air channel 4 which is provided along the wheel house 3 to lead some 9 of the airflows, flowing in the rotational direction around the tire 2 by being pulled by the rotation of the tire 2, inward from the rear of the tire 2 and to lead out some of the airflows from the front of the tire 2, and a communication passage 6 which communicates a midway part of the air channel 4 and the inside of the engine compartment 5 with each other. In the air channel 4, a cross-sectional area is reduced toward a downstream side from an upstream side in a predetermined area C, and a junction of the air channel 4 and the communication passage 6 is provided on the downstream side with respect to the predetermined area C.