A control system is provided with a control valve control unit for controlling a control valve, a data acquisition unit for acquiring, while an operation directive for driving a hydraulic cylinder is outputted, data pertaining to an operation directive value and a cylinder speed, and a derivation unit for deriving, on the basis of the data acquired by the data acquisition unit, an operation characteristic about the direction of operation, with respect to the operation directive value, in each of a plurality of hydraulic cylinders. The control valve control unit controls, in data acquisition by the data acquisition unit, a control valve for one pilot oil passage, among a plurality of pilot oil passages, that is an object about which data is to be acquired, to open the one pilot oil passage, and controls control valves for the other pilot oil passages to close the other pilot oil passages.