a control apparatus of power steering device having functions of monitoring intermediate troubles such as offset or drift out of signal troubles of torque sensor , and limiting the current for limiting the assist function is presented . in a control apparatus of power steering device for controlling a motor on the basis of a current control value calculated from a steering assist command value calculated by calculating means on the basis of a steering torque generated on a steering shaft , and a current value of a motor for applying a steering assist force to a steering mechanism , wherein the difference of a main torque signal and a sub torque signal of a torque sensor for detecting the steering torque is stored preliminarily , and the difference of the main torque signal and the sub torque signal during operation is compared with the stored value , and at least the current control value is limited when the difference based on the comparison is a condition larger than a first prescribed value and continues for a time longer than a first prescribed time .