A parts list system used for part number management is composed of a parts
table database and a parts list controller. The parts table database
includes a parts list which stores a state data and a part number data.
The state data indicates a progress state of a part. And the part number
data includes a number of the part as an identifier. The parts list
controller inhibits change of the part number data, when the state data
indicates prohibition of the change of the part number data.