FIGS. 5A-5C are diagrams for explaining an etching step in the micro-oscillator manufacturing method of the first embodiment of the present invention, wherein FIG. 5A is a top plan view in the etching step, FIG. 5B is an A-A??? sectional view of FIG. 5A in the etching step, and FIG. 5C is a B-B??? sectional view of FIG. 5A in the etching step.