A calibration device for a work machine includes: a working equipment parameter acquiring unit acquiring working equipment parameters of members of first and second actuation units; a measurement value acquiring unit acquiring respective measurement values of the work machine body and first and second actuation units measured by an external measurement device; a first calibration unit calibrating the parameter related to the member of the first actuation unit acquired by the acquiring unit based on the measurement value of the first actuation unit acquired by the acquiring unit; and a second calibration unit calibrating the working equipment parameter of the member of the second actuation unit based on the working equipment parameter of the first actuation unit calibrated by the first calibration unit and the respective measurement values of the reference points of the work machine body and first and second actuation units acquired by the acquiring unit.