The engine mount plays a vital role in the improvement of riding comfort, driving quality and noise level. Its characteristics are specified through spring constant and damping ratio. It alone does not have sufficient characteristics in the required frequency range. In this paper, the desired spring constant and damping ratio are realized by using a discrete-time controlled actuator. We formulate this problem as a model matching problem, and control the plant to follow the reference model which has the desired spring constant and damping ratio. The plant is controlled by a discrete-time actuator, whereas the reference model is of continuous time. Therefore we minimize the error between reference model and plant by using an optimal regulator, taking into account the behavior between sampling times. We confirm the efficacy of this method by computer simulation.