Disclosed herein is a micro speaker capable of having a high-pitched sound speaker unit and a low-pitched sound speaker unit and allowing the respective speaker units to clearly reproduce an inherent sound without interference. The micro speaker for converting an electrical signal into an acoustic signal includes: a high-pitched sound speaker unit disposed in an outer case; and a low-pitched sound speaker unit disposed in the outer case together with the high-pitched sound speaker unit, wherein the high-pitched sound speaker unit and the low-pitched sound speaker unit are disposed in the outer case so that a high-pitched sound vibrating plate of the high-pitched sound speaker unit and a low-pitched sound vibrating plate of the low-pitched sound speaker unit have directions opposite to each other.