Disclosed herein is a method of manufacturing an inertial sensor using a polling method of a piezoelectric element performing a polling after packaging the piezoelectric element, the method of manufacturing an inertial sensor including: forming a driving electrode and a sensing electrode on a flexible substrate on which a piezoelectric material is deposited; electrically connection the driving electrode and the sensing electrode; packaging the flexible substrate; polling by applying voltage and heat to the driving electrode and the sensing electrode; and electrically separating the driving electrode from the sensing electrode by applying heat to the driving electrode and the sensing electrode.