In an electronic component mounting method of mounting electronic components on a substrate by means of soldering by using an electronic component mounting system having a screen printing apparatus and an electronic component mounting apparatus connected to each other to manufacture a mounting substrate, prior to a screen printing process, the positions of pattern holes provided in a screen mask are measured to calculate mask aperture data, and the coordinates of a mounting position when a component mounting operation is performed by a mounting head are calculated, on the basis of the mask aperture data. In this way, it is possible to calculate the positional deviation of solder, without measuring the position of solder after printing whenever the solder is printed, and to prevent defects in mounting due to the positional deviation of solder, which results in high productivity.