To provide a construction machine capable of encouraging an operator to perform the driving and the operation for enhancing fuel efficiency. The construction machine includes information providing means 30 to notify the operator of the information such as the operation and/or an operational method or the like to enhance the fuel efficiency. The present construction machine provides the information by monitor display on a monitor screens 26 that is provided in an operator's cabin 11. When operating machine levers 19 and 20 are positioned at a neutral position, if an engine 40 has the idle revolution number not less than a predetermined time, the information providing means 30 provides the information such as the operation or the like to enhance the fuel efficiency.