This A new technique to measure the unbalanced mass of a single plane rotor with a designed and fabricated balancing machine has been focused in this paper. Here, the unbalanced force of the rotor is transmitted to the vibrating deflector via a support and the amount of deflection is converted to corresponding change in electric voltage by using a proximity sensor. The shaft position is measured with the help of a light sensor. All the data these two transducers gather are presented to the computer simultaneously to plot two graphs showing the binary values of the corresponding sensors versus time. Comparing these graphs, the phase angle of the unbalanced force is determined. Further, the binary values of the proximity sensor is converted to corresponding displacement values. Using them for three known unbalanced masses, displacement versus unbalanced mass graph is plotted. The amount of unknown unbalanced mass for a measured displacement can be found from this graph.