Stereocilium which change mechanical stimuli into electrical signals play a role of transducer, and have a characteristic of high-sensitivity over broad dynamic range. Sensitivity and dynamic range is a major design conflict in conventional engineering sensor design. In this study we propose a mechanical inertial sensor model of mimicking negative stiffness and adaptation mechanism of stereocilia to apply into an engineering sensor design. Negative stiffness mechanism, which hypothesized by gating of ion channel mimicked using virtual active force and adaptation mechanism worked by active motor mimicked by moving virtual active force. We observe the sensitivity and frequency selectivity of an inertial sensor model in response to an input signal. Simulation results indicate that model has high sensitivity in small input signal and have specific frequency selectivity. This result can be applying to engineering design problem.