A method for fabricating a micro speaker is provided, including forming a package wafer and a device wafer by batch processing, bonding the package wafer and the device wafer to each other, and forming a diaphragm by isotropic-etching a back surface of the device wafer using a xenon difluoride (XeF2). As a result, a micro-electronic-mechanic system (MEMS) technology-based piezoelectric micro speaker having a wide frequency response range is realized, by batch processing, thereby providing simplified structure and processing and reducing fabricating cost.