A force control for contact with flexible objects using a reflected-wave rejection technique is presented in this paper. To satisfy the demands of precise and rapid control including contacts with flexible objects, force controls for a multi-mass resonant systems are required. Generally, force gains are set high in force control to achieve high compliance. However, high compliance by a high force gain leads to degradations of positional stabilities. Thus in order to attain adaptability to the environment while decreasing the positional fluctuation, environmental dynamics have to be controlled. Furthermore, to increase the operation speed, excitations of high order resonances should be suppressed. In this context, this paper considers the environmental dynamics as an infinite-mass and proposes an integrated controller design using a reflected wave rejection technique. In addition, a notch filter is integrated to compensate for the propagation delay of the reaction force. The effectiveness of the proposed method is confirmed through simulations.