To manufacture a small-sized antenna which can adjust a resonant frequency, and has a simple shape, and is difficult to be damaged, and is easy to find how to use the antenna, and has less errors in terminal connection when mounting.

The small-sized antenna is manufactured through a stage for preparing a common radiation conductor pattern 20 including a plurality of radiation conductor patterns corresponding to a plurality of resonant frequencies, a stage for selectively cutting out short-circuiting portions 26A-26D in the common radiation conductor pattern 20 according to a desired resonant frequency, and a stage for sealing the section except terminals 22 and 24 of radiation conductor patterns 20A, 20B, or 20C obtained at the previous stage. According to this method, a small-sized antenna with small number of terminals can be manufactured.