There is provided a remote server that receives a machine type, an operating day, a position, a load factor, an engine rotational speed, a traveling speed, and a fuel consumption amount. The remote server identifies a working position based on the position, selects past operating days of an operation status corresponding to a current load factor of the same machine at the same working position, identifies a minimum fuel consumption amount out of fuel consumption amounts corresponding to the selected past operating days, and compares a current fuel consumption amount with the past minimum fuel consumption amount. If the current fuel consumption amount is larger than the past minimum fuel consumption amount, the remote server transmits an engine rotational speed and a traveling speed during a working period of the minimum fuel consumption amount, to a predetermined communication terminal corresponding to information for machine identification.
