This component mounting system has a component mounting device that mounts a component on a substrate; a tape feeder (component supply device), which is loaded in the component mounting device, and which supplies the component; and a self-propelled component replenishing device, which automatically moves by holding a tape cassette (storing container) having a plurality of components stored therein, and which replenishes the tape feeder (component supply device) with the components stored in the tape cassette (storing container).