A compressor for a gas turbine having means for determining whether a blade of the compressor has been deformed includes a rotor having an outer circumference on which a blade is formed; a monitoring part for monitoring a driving state of the blade in order to acquire monitoring information on the driving state of the blade; and a control part for determining whether the blade has been deformed based on the monitoring information. The monitoring part detects time points at which the trailing edge and the leading edge of the blade pass and acquire the detection time information of the detected time point. The control part receives the detection times of the trailing edge and the leading edge from the monitoring part and determines whether the blade has been deformed based on the detection time of the trailing edge and the detection time of the leading edge.