A cooling device for an electronic machine includes an airflow channel through which external air passes, an air inlet duct through which external air is introduced and which is disposed at an upper front surface of the airflow channel and extends perpendicularly to the airflow channel, a blower fan disposed in the air inlet duct to draw in external air through the air inlet duct, an air outlet duct disposed at a lower portion of the airflow channel to discharge air from the airflow channel, and a heat-radiating unit disposed to the rear of a circuit board mounted with electronic components on a front surface thereof to absorb heat from the circuit board. The heat-radiating unit is located, apart from the blower fan, in the airflow channel. Through the improved cooling airflow structure, cooling efficiency is increased, noise is reduced and continuous cooling operation is achieved.