A sirocco fan 4 equipped with a scroll-type casing 1, which has a tongue section 3 that is the starting point of the scroll, and a multi-bladed centrifugal fan 2, which is accommodated within the casing. When a region in the casing located in the vicinity of 90° from the tongue section 3 in the fan rotation direction is set as a flat section 6, the shortest distance between the tongue section 3 and the fan 2 is X, and the shortest distance between the flat section 6 and the fan 2 is Z, the distance X and the distance Z are set in the range 1.0 ≤ X/Z ≤ 1.5.
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