A disclosed coaxial audio speaker may include a treble sound unit and a bass sound unit co-axially surrounding the treble sound unit. The bass sound unit may be in form of a single magnetic gap mechanism and have a magnetic-conductive base. The magnetic-conductive base may be with an auxiliary magnetic adjoining space and a coil movement space adjacent to the auxiliary magnetic adjoining space. A magnet, a vibrating vocal tone diaphragm along with a wiring board may be disposed within the coil movement space. A bass vibration audio source point and a treble vibration audio source point may be at the same horizontal level. Therefore, the size of the audio speaker may be reduced. And the broader electricity adjustability may be achieved as the bass vibration audio source point and the treble vibration audio source point may be horizontally aligned.