1. A unit cost estimation system comprising: a storage device configured to store a model unit machining cost and a model indexical ratio concerning a business of a business unit; at least one inputting device configured to input cost factors and cost information concerning the business; a processing device configured to determine an actual unit machining cost and an actual indexical ratio based on the cost factors and cost information input by the inputting device; and at least one outputting device configured to output the actual unit machining cost and actual indexical ratio determined by the processing device while comparing the actual unit machining cost and actual indexical ratio with the model unit machining cost and model indexical ratio.