The inner peripheral surface 35 of the upper plate 32 of the first case 31 has a first inclined surface 35 a radially facing the seal holding member 62 of the motor 60. The inner peripheral surface 52 of the seal fixing member 50 has a second inclined surface 52a radially facing the seal holding member 62 of the motor 60. The seal holding member 62 of the motor 60 has an outer peripheral surface 63 facing the inner peripheral surface of the fan case 22 (the inner peripheral surface 35 of the case body 30 (the first case 31) and the inner peripheral surface 52 of the seal fixing member 50). are doing. The outer peripheral surface 63 has a third slope 63a and a fourth slope 63b along the axial direction of the rotation shaft 61a. The third slope 63a and the fourth slope 63b have a larger outer diameter on the far side than on the near side. The seal member 70 is disposed in an annular space surrounded by the first slope 35a, the second slope 52a, the third slope 63a, and the fourth slope 63b.第１ケース３１の上板３２の内周面３５は、モータ６０のシール保持部材６２と径方向に対向する第１斜面３５ａを有している。シール固定部材５０の内周面５２は、モータ６０のシール保持部材６２と径方向に対向する第２斜面５２ａを有している。モータ６０のシール保持部材６２は、ファンケース２２の内周面（ケース本体３０（第１ケース３１）の内周面３５及びシール固定部材５０の内周面５２）と対向する外周面６３を有している。外周面６３は、回転軸６１ａの軸方向に沿って第３斜面６３ａと第４斜面６３ｂとを有している。第３斜面６３ａと第４斜面６３ｂは、互いに近い側の外径に比べ、互いに遠い側の外径が大きい。シール部材７０は、第１斜面３５ａ、第２斜面５２ａ、第３斜面６３ａ、第４斜面６３ｂにより囲まれる環状の空間に配設されている。
