A maintenance device for a construction machine includes: an abnormality detection means for detecting abnormality of an apparatus installed on the construction machine; an abnormality information output means for outputting abnormality information about the apparatus detected by the abnormality detection means; and a maintenance mode setting means for setting a maintenance mode for performing a maintenance work of the apparatus, wherein the abnormality information output means for eliminating negation or output of the information, if any abnormality of the apparatus is detected in a state in which the maintenance mode is set by the maintenance mode setting means.