The invention provides a fan. The fan comprises a hub, a rotating shaft, a sleeve, an oil seal bearing and a locating ring; the hub comprises an inner top surface, wherein an oil stopping groove is formed in the inner top surface; the rotating shaft is connected to the hub; the oil seal bearing is arranged in the sleeve and comprises a ring-shaped body, and the ring-shaped body supports the rotating shaft; and the locating ring is arranged between the hub and the oil seal bearing and comprises an oil stopping flange, and the oil stopping flange extends into the oil stopping groove. According to the fan, the problem that an existing fan needs to use an oil seal to prevent lubricating oil from being thrown out when rotating and the problem that the supporting effect of a bearing is lowered and the service life of the bearing is shortened due to the fact that the height ratio of the oil seal is too large can be solved. Meanwhile, the oil seal effect can be directly realized without using an additionally-arranged oil seal component, the supporting effect can be improved, and the service life can be prolonged.