PURPOSE: To increase air blasting efficiency by providing a boss with first blades, which extend toward the outside in the radial direction at a prescribed interval around the axis of the boss, and also providing the boss with second blades, which are comparatively small and located between the first blades.

CONSTITUTION: A fan 40 as an outdoor unit for an air conditioner is used to blast the air on the outdoor-heat-exchanger-side to the side of a blow-off port, which is formed onto an outdoor unit casing. The fan 40 is driven by a motor. Such a fan 40 is consisted of a nearly cylindrical boss 41 made of synthetic resin and first and second blades 42 and 43, both of which are also made of synthetic resin. The first blades 42 are formed so as to extend in the radial direction of the boss 41 at an angle-difference of 90° with each other. Meanwhile, each second blade 43 is installed between the first blades 42 and formed in such a way that its span l less than a half of the span L of the first blade 42.