An electronic-component mounting system includes: mounting lines each including an electronic-component mounting apparatus; an operation information processor which collects operation information of the electronic-component mounting apparatus, applies a statistical process on the operation information, and produces operation quality information of the mounting lines; and a portable information terminal accessible to the operation information processor by wireless communication. An identification information transmission section which transmits identification information for identifying each of the mounting lines is disposed in each mounting line, and a reception section which receives the identification information is disposed in the portable information terminal. The portable information terminal displays on a display section thereof the operation quality information of one of the mounting lines located near the portable information terminal based on the identification information transmitted from the mounting lines.