In an electronic component mounting system 1 configured by coupling electronic component mounting devices M1 to M4A each having a first substrate transport mechanism 12A and a second substrate transport mechanism 12B together, the electronic component mounting device M4A includes a first tray feeder 20A that stores an electronic component extracted by a first mounting head 15A of a component mounting mechanism as a first work operation mechanism, and a second tray feeder 20B that stores an electronic component extracted by a second mounting head 15B of a component mounting mechanism as a second work operation mechanism.