An inner peripheral surface 35 of an upper plate 32 of a first case 31 has a first inclined surface 35a that faces a seal holding member 62 of a motor 60 in the radial direction. An inner peripheral surface 52 of a seal fixing member 50 has a second inclined surface 52a that faces the seal holding member 62 of the motor 60 in the radial direction. The seal holding member 62 of the motor 60 has an outer peripheral surface 63 that faces an inner peripheral surface (the inner peripheral surface 35 of a case body 30 (first case 31) and the inner peripheral surface 52 of the seal fixing member 50) of a fan case 22. The outer peripheral surface 63 has a third inclined surface 63a and a fourth inclined surface 63b along the axial direction of a rotary shaft 61a. The outside diameter on a side where the third inclined surface 63a and the fourth inclined surface 63b are far from each other is greater than the outside diameter on a side where the third inclined surface 63a and the fourth inclined surface 63b are near each other. A sealing member 70 is installed in an annular space that is surrounded by the first inclined surface 35a, the second inclined surface 52a, the third inclined surface 63a, and the fourth inclined surface 63b.Selon l'invention, une surface périphérique interne (35) d'une plaque supérieure (32) d'un premier boîtier (31) comprend une première surface inclinée (35a) qui fait face à un élément de maintien de joint d'étanchéité (62) d'un moteur (60) dans la direction radiale. Une surface périphérique interne (52) d'un élément de fixation de joint d'étanchéité (50) comprend une deuxième surface inclinée (52a) qui fait face à l'élément de maintien de joint d'étanchéité (62) du moteur (60) dans la direction radiale. L'élément de maintien de joint d'étanchéité (62) du moteur (60) comprend une surface périphérique externe (63) qui fait face à une surface périphérique interne (la surface périphérique interne (35) d'un corps de boîtier (30) (premier boîtier (31))
