An axial-flow fan includes: a hub; and blades disposed on an outer peripheral surface of the hub and spaced apart from each other in a circumferential direction. The hub includes: an outer wall having a tubular shape; an inner wall having a tubular shape and being disposed radially inward of the outer wall; a boss to which a shaft is mounted and that is disposed radially inward of the inner wall; a first sidewall connecting an end portion of the outer wall that is closer to a first side in a rotation axis direction of the hub with an end portion of the inner wall that is closer to the first side in the rotation axis direction; and a second sidewall connecting the end portion of the inner wall with an end portion of the boss that is closer to the first side in the rotation axis direction.