A compressor control device controlling a compressor, the compressor comprising: a plurality of upstream-most compressor bodies disposed furthest upstream; at least one stage of downstream compressor body which is disposed downstream from the plurality of upstream-most compressor bodies and in which a gas merged after outflow of gases from the plurality of upstream-most compressor bodies flows; an inlet guide vane provided in the vicinity of an inlet of each of the plurality of upstream-most compressor bodies and configured to control a flow rate of the gas flowing in the corresponding upstream-most compressor body; a plurality of upstream-most flow rate detectors provided in the vicinity of the inlets or outlets of the plurality of upstream-most compressor bodies and configured to generate upstream-most flow rate detection values by detecting flow rates flowing through the corresponding upstream-most compressor bodies; a post-merger pressure detector configured to generate a post-merger pressure detection value by detecting a post-merger pressure of the gas flowing out from each of the plurality of upstream-most compressor bodies; and an outlet pressure detector configured to generate an outlet pressure detection value by detecting an outlet pressure of a downstream-most compressor body disposed furthest downstream among the downstream compressor bodies, the compressor control device comprising: an inlet guide vane opening degree control unit configured to control an opening degree of the inlet guide vane, wherein the inlet guide vane opening degree control unit comprises: an inlet guide vane opening degree command value generation unit configured to generate an inlet guide vane opening degree command value from the outlet pressure detection value; and a plurality of inlet guide vane opening degree command value correction units configured to correct the inlet guide vane opening degree command value based on the post-merger pressure detection value and the corresponding upstream-most flow rate detection value in each of the plurality of upstream-most compressor bodies. a plurality of upstream-most compressor bodies disposed furthest upstream; at least one stage of downstream compressor body which is disposed downstream from the plurality of upstream-most compressor bodies and in which a gas merged after outflow of gases from the plurality of upstream-most compressor bodies flows; an inlet guide vane provided in the vicinity of an inlet of each of the plurality of upstream-most compressor bodies and configured to control a flow rate of the gas flowing in the corresponding upstream-most compressor body; a plurality of upstream-most flow rate detectors provided in the vicinity of the inlets or outlets of the plurality of upstream-most compressor bodies and configured to generate upstream-most flow rate detection values by detecting flow rates flowing through the corresponding upstream-most compressor bodies; a post-merger pressure detector configured to generate a post-merger pressure detection value by detecting a post-merger pressure of the gas flowing out from each of the plurality of upstream-most compressor bodies; and an outlet pressure detector configured to generate an outlet pressure detection value by detecting an outlet pressure of a downstream-most compressor body disposed furthest downstream among the downstream compressor bodies, the compressor control device comprising: an inlet guide vane opening degree control unit configured to control an opening degree of the inlet guide vane, wherein the inlet guide vane opening degree control unit comprises: an inlet guide vane opening degree control unit configured to control an opening degree of the inlet guide vane, wherein the inlet guide vane opening degree control unit comprises: an inlet guide vane opening degree command value generation unit configured to generate an inlet guide vane opening degree command value from the outlet pressure detection value; and a plurality of inlet guide vane opening degree command value correction units configured to correct the inlet guide vane opening degree command value based on the post-merger pressure detection value and the corresponding upstream-most flow rate detection value in each of the plurality of upstream-most compressor bodies.