An inkjet image-forming apparatus includes an array inkjet head that is formed along a printing path through which a paper on which an image or a test image is formed is discharged, and includes a length corresponding to the width of the paper, and a plurality of nozzles to eject ink, and a missing nozzle detection unit formed along a missing nozzle detection path that is connected to the printing path to scan an image or a test image formed by the array inkjet head by transporting the paper (P), on which the test image is formed, towards the printing path, and a method thereof.