A novel electro-chemical capacitor was tried to synthesis by assemble carbon powder with manganese oxide using an ultra-sonication in KMnO₄ solution. (ultrasonic sample). A reference sample was prepared by same condition except for radiation of ultra-sonication (settle sample). Both ultrasonic sample and settle sample show the composite of manganese oxide and carbon. Additionally, layered manganese oxide phase was observed in the ultrasonic samples. Surface atomic ratio of Mn/C decreased corresponding with increasing of used solution volume from 25 ml to 250 ml. The composite prepared using 100ml solution was greatly affected by the ultra-sonication. On the other hand, the amount of manganese on the surface has increased with the increasing of the irradiation of energy among the ultrasonic sample. The amount of manganese deposition was almost saturated with 100 mW/cm³. Cyclic voltammetry curves of the obtained composites were influenced by scanning speed. The ultrasonic sample shows higher electrical capacitance than the settle sample in various conditions.