Disclosed is a frequency analyzer for a MEMS based cochlear implant with self power supply. The frequency analyzer for a MEMS based cochlear implant includes: an upper structure including a first substrate, and a nano wire contact portion formed under the first substrate and coated with a high conductivity metal; and a lower structure including a second substrate having a space filled with a fluid and an upper portion of which is opened, a membrane formed on the fluid filled in the space of the second substrate, a first electrode formed on the membrane, and a nano wire formed on the first electrode and having the piezoelectric characteristics related to an arbitrary direction in which the nano wire is grown.