A locking mechanism is used to prevent a connector coupled to an device from accidently disengaging from the device. A cable extends from the connector. The locking mechanism includes a supporting bracket fixed to the device, and a locking member mounted to the supporting bracket and slidable between a locking position and an unlocking position. The supporting bracket defines a retaining hole. The locking member includes a protrusion and a block. When the locking member slides to the locking position, the block abuts against the connector. The protrusion is engaged in the retaining hole to keep the locking member at the locking position. When the locking member slides to the unlocking position, the block is spaced from the connector to provide an operation space for removing the connector from the device.