Sound source localization is always of great value in many engineering applications. In this paper, a new instrument is designed to accomplish the purpose of localizing the sound source by a relatively compact structure. This bionics structure is designed to mimic the localization function of the ears of the parasitoid fly Ormia ochracea, and it consists of three elastic diaphragms, three bars which connected to the diaphragms, and the other mechanical components. The analysis of this structure’s dynamic behavior shows that the incident angles of the sound have special relationship to the responses of this instrument, and the incident angles can be estimated by detecting the vibrations of the three elastic diaphragms. Compared with traditional microphone arrays, this instrument has the advantage of compaction and higher integrated level.