PURPOSE: To improve the wind feeding characteristic by making the gap between the outer periphery of a fan blade and the inner periphery of a case which is formed in case of cutting by the plane vertical to a rotor shaft, constant with respect to the rotor shaft.

CONSTITUTION: A blower is constituted of a hub 3 having a fan blade 4 installed, stay 2, and a case 1. The case 1 and a rotor are constituted in the position relation where the gap between the outer periphery of a fan blade and the inner periphery of the case which is formed in case of cutting by the plane vertical to a rotor shaft is kept constant. Therefore, the wind sent in can be taken in free from uselessness, and since the gap 5 between the outer periphery 8 of the fan blade and the inner periphery 9 of the case in the vicinity of a discharge port 7 is little, generation of swirl is suppressed, and the wind feeding characteristic can be improved.