The author has proposed a regulator-type adaptive nonstationary control (ANSC) method using time-varying Riccati equations (TVREs). ANSC method generates the solutions of TVREs and the responses of a controlled object simultaneously. The time-varying feedback gains are obtained by real-time computations in actual implementations. Therefore, ANSC method can realize some adaptive control based on varying parameters of a controlled object. The regulator-type controllers are applicable to Position-To-Position control problems. In mechanical structures such as information precision machinery, the switching from a velocity servo controller to a position servo controller is often utilized. ANSC method can not be applied to that case. Then, this study proposes an adaptive nonstationary servo control (ANSSC) method based on the idea of ANSC method. ANSSC method realizes a unified design of both the servo controllers and the smooth mode switching. Its effectiveness is verified theoretically and experimentally by applying the method to a positioning control problem for the system consisting of an X-Y table and a flexible structure on the table.