An on-site system construction support tool 11 has a display device that displays a configuration example of an on-site system of a plurality of machines 1601-1607, 1610, 1611. The display device opens a process window 1100 having a plurality of process buttons 1101-1112, which identify processes 1501-1511 required for the on-site system, when one of the process buttons is operated, causing the display device to open a setup window 1210, 1220, 1230, 1240, 1250, 1260 for specifying the machine to be used in the associated process. The burden that is imposed on the environment by the on-site system is calculated in accordance with information concerning the fuel consumption of the specified machine and the amount of work and displayed. This makes it possible to flexibly support the construction of the on-site system and calculate a value of the expected environmental burden.