A parts mounting system includes: a parts checking section that detects parts information which is identification information applied to the electronic parts and includes a parts code for specifying parts of the electronic parts and a parts maker code for specifying the parts maker and checks the detected parts information with parts information previously registered in a storing part; and a parts data generation section that, when the detected parts information is unregistered parts information in which the parts code is stored in the storing part and the parts maker code of the parts code is not stored in the storing part, generates parts data of the electronic parts relating to the unregistered parts information based on previously registered parts data having the same parts code.