This paper describes two kinds of velocity-command-type trajectory control systems of a two-link flexible arm and experimental results using joint actuators and an active mass damper. One servo system has been developed which consists of a trajectory controller based on model-following servo control for the imaginary rigid body coordinate and an elastic deformation controller on LQI control. This system was shown to be effective from the experimental results and has the merit that controller gains can be easily calculated as constant values in spite of the flexible arm nonlinearity. Another servo system consists of a trajectory controller for the elastic deformation caused by gravitational force and a vibration controller using an active mass damper, which was also found to be effective.