An experimental study has been carried out to make clear the effect of electric field on release of supercooling state of water in soft PVC (polyvinyl chloride) tubes arranged side by side in close contact. Each tube is filled with water and silicone oil. The two liquids make a liquid-liquid interface, and the interface and inner surface of the tube form a triple-phase boundary in each tubes. The electric field is applied between tubes at both ends, by use of a pair of wire electrode to initiate instability of the boundary and the interface. The experimental conditions are -5℃in temperature and 35kV DC in applied voltage. As a result, instability of the triple-phase boundary and liquid-liquid interface in each tube is observed by applying the electric field. The instability caused the release of supercooling state of water in tubes. In case of two tubes, supercooling state of water in both tubes was released within 120 seconds. In case of three tubes, however, the release was not observed in several tubes within 180 seconds.