A negative carbon-ion source has been designed and tested at the Dongguk University accelerator mass-spectrometer facility in Korea. The beam-extraction conditions in the ion-source test stand were determined experimentally. Negative carbon-ion beam transport using a dipole magnet for separation was also investigated. Negative carbon was extracted using a 2.5 standard cubic centimeters per minute (sccm) CO2 flow at a −30.0 kV high voltage applied to the plasma electrode. The applied arc current, ion-source magnet could adjust various conditions, and dipole magnet could produce fields up to 5000 G. The effects of various operating conditions and geometrical configurations on beam transport were evaluated in this study.