A fan structure automatically mountable on a system circuit board includes a fan. The fan includes a fan frame main body. A connector connection section is disposed on the fan frame main body for connecting with a fan end connector, whereby the fan end connector can be assembled with the fan frame main body. Accordingly, when the fan is mounted on the system circuit board, the fan end connector can be directly pressed down by means of an automated device to plug into the circuit board end connector. Therefore, the manufacturing process can be automated.