The unbalance on an axial fan engine causes vibration and noises in a small open wind tunnel construction circuit. The unbalance is not only speeding up the damage to the engine but also disrupt the convenience surrounding the engine, especially for the engine users. In this research, measurement analysis is done to find the cause of the unbalance. Initial vibration measurement results show the amplitude exceed[s] the ISO 10816-3 standard limit (0.292 G-S equal to 15.45 mm/s). After going through the balancing process, the unbalance of the axial fan decreases by 84% with the amplitude of 0.047 G-S equal to 2.5 mm/s, so the engine vibration and the vibrations of its surrounding rope.