This supercharger is provided with: a centrifugal compressor having an impeller linked to a rotating shaft; a bearing housing for accommodating a bearing for rotatably supporting the rotating shaft, the bearing housing facing the rear surface of the impeller; a head tank provided to the bearing housing and configured so as to store lubricating oil supplied to the bearing; a labyrinth seal provided between the rear surface of the impeller and the bearing housing, the labyrinth seal including an annular labyrinth seal plate and a labyrinth fin integrated with the labyrinth seal plate; and a heat-transfer-promoting means configured so as to promote heat transfer between the lubricating oil stored in the head tank and the labyrinth seal plate.