Disclosed herein is an inertial sensor. An inertial sensor according to preferred embodiments of the present invention is configured to include a membrane, a plurality of first electrodes patterned on the membrane, a plurality of piezoelectric elements patterned on the first electrodes, and a second electrode integrally formed to cover the piezoelectric elements. By the configuration, the piezoelectric element is encapsulated with the second electrode that is integrally formed to prevent water or humidity from being permeated into the piezoelectric element, thereby preventing physical properties of the piezoelectric element from being changed or preventing the piezoelectric element from being delaminated.