provided is a thermal displacement correction device for a working machine that includes a thermal displacement correction amount calculation unit for calculating a thermal displacement correction amount and configured to correct a thermal displacement amount caused by heat generated and radiated from the working machine and changing with time by the thermal displacement correction amount , the thermal displacement correction device for the working machine including : a correction error coefficient storage memory ; a correction precision calculation unit configured to calculate the correction precision of the thermal displacement correction amount based on the thermal displacement correction amount and the correction error coefficient ; and a correction precision degradation notification unit .