This thesis presents design and application of active damper using electrodynamic actuator for active vibration control. The features of this damper are following. It is mount-type to pile up on the vibrating structure and it is divided into controller, sensor and actuator part for convenient application. In this study, we designed the active damper and tested performance. We divide the damper into magnetic, electric and mechanical part, discuss the theory of each part and explain the design procedure. Then, we determined the design parameters and manufactured the damper. It has some problems such as nonlinear spring constant and poor efficiency. We designed another damper to improve these problems. We tested performance to show that it is improve the proposed problems. To verify that this damper is applicable to vibration control, we reduced vibration of cantilever beam using the damper.