A module evaluation method and system which can quickly determine overall effectiveness of the modular construction method in an automatic manner, taking into account the transportation cost and so on. A module evaluation unit prepares constructed-equipment physical quantity data from constructed-equipment layout data, and determines an in-module unit-rate reduction effect resulted from executing construction work of the constructed equipment in the module in a factory where working efficiency is higher than a field. The module evaluation unit also determines a module transportation cost effect, a module temporary construction cost effect, and a density reduction effect that is resulted from a reduction of density in a space not occupied by a module with application of modularization and efficiency of installation work is increased. The module evaluation unit further determines a field physical-quantity reduction effect resulted from a reduction of physical quantity in the field and from a reduction of various overhead costs with application of the modularization. The determination results are displayed on a display.