A centrifugal fan includes an impeller and a motor which rotates the impeller. The impeller includes an upper shroud, a lower shroud, and blades arranged therebetween. A rotor of the motor is attached to an attachment part of the lower shroud. In a section passing a rotary shaft of the impeller, the rotor and the attachment part are provided at a more outer side than a circle having a center on a line passing an upper end portion of an inlet opening at an inner side and parallel to the rotary shaft of the impeller, having a radius of 80% of a distance from the upper end portion of the inlet opening to a surface of the lower shroud below the upper end portion, and being tangent to the surface of the lower shroud or passing an end edge portion of the lower shroud.