PURPOSE: To provide cooling structure for an electronic apparatus, in which an electronic unit that needs forced cooling and another kind of electronic unit are cooled, and the latter electronic unit is cooled well, along with a small space at installation.

CONSTITUTION: In a cooling structure for an electronic apparatus, a separation- type fan unit 30 includes a box-shaped ventilating unit 50 with front and back faces opened and a fan board 40 provided under the ventilating unit 50. The ventilating unit 50 is made up of a pair of side plates, a ceiling plate 55 with discharging openings in rows, and a separation 51 sloped down forward or backward in a box body. The separation-type fan unit 30 is mounted on a desired middle stage in a rack 1, and an electronic unit 10 that requires forced cooling is put on a lower stage in the separation-type fan unit 30, while another kind of electronic unit 60 is put on the upper stage in the separation-type fan unit 30.