To provide a controller for a servo valve allowing setting of a target value having a wide dynamic range in fluid pressure control, and allowing acquisition of a stable control characteristic even in a nonlinear area.

This controller for the servo valve has: a setting part generating a prescribed reference input signal from the target value of a control amount to the servo valve and outputting it; a detection part detecting the control amount of the servo valve, and outputting a feedback amount; a comparison part comparing the reference input signal outputted from the setting part and the feedback amount outputted from the detection part, and outputting a difference thereof; and an adjustment part receiving the difference outputted by the comparison part, and outputting an operation amount imparted to the servo valve. The controller has a variable gain adjustment part inserted between the comparison part and the adjustment part, adjusting the difference outputted by the comparison part to a prescribed level according to a level of the reference input signal, and outputting it to the adjustment part.

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