An electronic circuit component mounting system comprising: a mounter main body; (a) a circuit substrate conveying and holding device (32, 34, 42, 44) held on the mounter main body that is configured to convey and fix and hold a circuit substrate, (b) a head main body that is configured to be moved with respect to the mounter main body by a head moving device to any position on a movement plane inside the mounter main body, (c) at least one head-side feeder held on the head main body that is configured to supply electronic circuit components, (d) a mounting device that is configured to receive the electronic circuit component from the head-side feeder and to mount the electronic circuit components on a circuit substrate held by the circuit substrate conveying and holding device (32, 34, 42, 44) using multiple component holding tools provided on the head main body, (e) a first control device that is configured to control the circuit substrate conveying and holding device (32, 34, 42, 44), the head moving device, the head-side feeders, and the mounting device, and characterized by (f) a second control device that is configured to perform control such that, while a component holding tool from the multiple component holding tools positioned at a component mounting position is contacting an electronic circuit component (150, 152) and while the electronic circuit component (150, 152) is contacting the circuit substrate, another component holding tool from the multiple component holding tools positioned at a component pickup position of a component supplied from the head-side feeder and an electronic component are brought into contact with each other, and the electronic circuit component and the head-side feeder are brought into contact with each other. (a) a circuit substrate conveying and holding device (32, 34, 42, 44) held on the mounter main body that is configured to convey and fix and hold a circuit substrate, (b) a head main body that is configured to be moved with respect to the mounter main body by a head moving device to any position on a movement plane inside the mounter main body, (c) at least one head-side feeder held on the head main body that is configured to supply electronic circuit components, (d) a mounting device that is configured to receive the electronic circuit component from the head-side feeder and to mount the electronic circuit components on a circuit substrate held by the circuit substrate conveying and holding device (32, 34, 42, 44) using multiple component holding tools provided on the head main body, (e) a first control device that is configured to control the circuit substrate conveying and holding device (32, 34, 42, 44), the head moving device, the head-side feeders, and the mounting device, and characterized by (f) a second control device that is configured to perform control such that, while a component holding tool from the multiple component holding tools positioned at a component mounting position is contacting an electronic circuit component (150, 152) and while the electronic circuit component (150, 152) is contacting the circuit substrate, another component holding tool from the multiple component holding tools positioned at a component pickup position of a component supplied from the head-side feeder and an electronic component are brought into contact with each other, and the electronic circuit component and the head-side feeder are brought into contact with each other.