In the present report, the forced vibration response of a beam structure having an electromagnetic damper with velocity feedback is investigated theoretically and experimentally. The beam structure is subjected to a harmonic exciting force, and the vibrations are controlled by the electromagnetic damper consisting of an electromotive linear actuator and a velocity sensor using rare-earth magnets as well as control circuit. In the analysis, the simultaneous equations under Bernoulli-Euler bending theory in consideration of both the beam structure and the control system are solved exactly. Furthermore, the effects of the amplifier gain of the control system upon the vibration control efficiency and the response of the system are clarified.