A force redistribution method for compensating actuator breakdown of vibration-isolation tables is studied. The vibration-isolation table is supported by eight pneumatic actuators and has a redundant number of actuators with respect to the degrees of freedom of table motion. We propose a force redistribution method that utilizes the redundancy of the actuators. In the proposed method, when some of the actuators break down, their output forces are redistributed on the unbroken actuators. We construct a detailed mathematical model in view of the behavior of the vibration-isolation table when some of the actuators break down. A type 1 digital servo system is applied to control the vibration and position of the vibration-isolation table. We perform numerical simulations in which some of the actuators break down at a certain time and the pressure of the broken actuators decreases at a constant rate. The numerical simulations examine the effectiveness of the proposed method.