Observer-based force compensations are applied in an assembly of magnetized components. In the target assembly, a ferromagnetic component approaches a magnetized component. Then they are pulled toward each other due to the attractive force between them. It sometimes causes overshoot and collision although the positioning control system is designed to have no overshoot without such a force. To solve this problem, force compensation is added to the position control. An actuator generates the force to cancel the attractive force based on the force estimated by an observer. Two observers are compared. One is disturbance observer and the other is full-order observer. Experimental results demonstrate that the usefulness of the observers to estimate the attractive force and the effectiveness of the force compensation.