To calculates the costs needed on a production line by specific cost calculated objects.

This manufacturing cost calculation system has a storage means 3 which stores cost data by cost items, characteristic parameters regarding a manufacturing device, and use time rate data by the cost-calculated objects of the manufacturing device, a load rate arithmetic means 21 which reads the characteristic parameters regarding the manufacturing device and the use time rate data by the cost-calculated objects out of the storage means 3 and calculates load rates by the cost-calculated objects for allocating the costs for common cost parts of the cost data by the cost items by the cost-calculated objects, and a load cost arithmetic means 22 which reads the cost data by the cost items out of the storage means 3, allocates the costs for the common cost parts by the cost-calculated objects according to the load rates by the cost-calculated objects and calculates manufacturing costs by the cost-calculated objects.