The invention relates to an apparatus for fixing a fiber at the center of a ferrule comprising a heating stage, a temperature controller, at least one charge-coupled device, a first moving stage, a processor unit and a solder material feeder. The heating stage is used for mounting and heating the ferrule. The charge-coupled devices are used for monitoring the position of the fiber in the ferrule, and one of the charge-coupled devices is connected to the processor unit so as to measure the eccentric offset of the fiber in the ferrule. The first moving stage is used for mounting the fiber and adjusted the position of the fiber so that one end of the fiber is disposed near a inlet of the ferrule and inserting the fiber into the ferrule after alignment. The solder material feeder is used for sealing the ferrule with the solder material. The present invention also relates to a method for fixing a fiber at the center of a ferrule.