Silver nanowire transparent conducting films (TCFs) are expected to be alternative materials for indium tin oxide TCFs. Silver nanowires are typically synthesized by polyol method. It requires protective agents in order to achieve an anisotropic crystal growth, however, protective agents cover the surface of nanowires, and hence decrease conductivity of electrodes. In this study, we have synthesized needle-shaped silver carboxylates by ultrasound irradiation without any protective agent, and then obtained silver nanowires by exposing them to hydrazine gas. Silver carboxylates were synthesized by ultrasound irradiation to mixture that contains silver(I) oxide, carboxylic acids(2-6C), and ethanol. These carboxylates were put onto glass substrate, and then exposed to hydrazine gas (vaporized hydrazine monohydrate) to reduce. The obtained samples were characterized by FE-SEM, XRD, TG-DTA, and UV-Vis. Long needle-shaped silver carboxylates were observed after ultrasound irradiation. In contrast to stirrer, we obtained well-dispersed silver carboxylates by ultrasound irradiation. In addition, it was confirmed that the reaction rate is greater than that of stirrer. These results are due to effects of ultrasound, such as strong dispersive power, erosion, and high temperature-pressure reaction field. Silver nanowire TCF were prepared by reducing silver carboxylates. This film indicated low resistivity and high transparency.