To accurately grasp a generation situation of a warning generated in an operation machine, the operation machine is provided with: warning generation means 55 adapted to determine whether or not there is abnormality, and in the case where there is abnormality, generate a warning; warning storage means 56 adapted to store warning information on the warning; display means adapted to display the warning information stored in the warning storage means 56; and warning erasing means adapted to erase the warning information, wherein the warning storage means 56 is configured to store warning information on a warning generated after the erasure by the warning erasing means 57.