A component mounting line in which multiple component mounters are arranged along a conveyance path of a circuit board and, in the multiple component mounters, a component supplied from an automatically exchangeable feeder, which is set in a feeder setting section of each component mounter, is mounted on the circuit board, wherein the automatically exchangeable feeder being among a set of multiple exchangeable feeders and the feeder setting section is configured to set the multiple automatically exchangeable feeders in slots; the component mounting line comprising: - an automatic exchanging device configured to move along a front face of the component mounting line in an arrangement direction of the multiple component mounters to automatically exchange the automatically exchangeable feeder with respect to the feeder setting section of each component mounter; characterized in that the component mounting line further comprises: - a feeder arrangement monitoring section configured to monitor an arrangement status of the automatically exchangeable feeder set in the feeder setting section of each component mounter; and - a control device configured to control an operation of the automatic exchanging device, wherein when it is determined that a number of empty slots of the feeder setting section of any one of the component mounters is equal to or larger than a predetermined value based on a monitoring result of the feeder arrangement monitoring section, the control device controls the operation of the automatic exchanging device such that an automatically exchangeable unit is set in one of the empty slots of the feeder setting section of the component mounter; wherein the automatically exchangeable unit is a unit that can be automatically exchanged with respect to the one empty slot of the feeder setting section by the automatic exchanging device. the component mounting line comprising: - an automatic exchanging device configured to move along a front face of the component mounting line in an arrangement direction of the multiple component mounters to automatically exchange the automatically exchangeable feeder with respect to the feeder setting section of each component mounter; - an automatic exchanging device configured to move along a front face of the component mounting line in an arrangement direction of the multiple component mounters to automatically exchange the automatically exchangeable feeder with respect to the feeder setting section of each component mounter; characterized in that the component mounting line further comprises: - a feeder arrangement monitoring section configured to monitor an arrangement status of the automatically exchangeable feeder set in the feeder setting section of each component mounter; and - a control device configured to control an operation of the automatic exchanging device, wherein when it is determined that a number of empty slots of the feeder setting section of any one of the component mounters is equal to or larger than a predetermined value based on a monitoring result of the feeder arrangement monitoring section, the control device controls the operation of the automatic exchanging device such that an automatically exchangeable unit is set in one of the empty slots of the feeder setting section of the component mounter; - a feeder arrangement monitoring section configured to monitor an arrangement status of the automatically exchangeable feeder set in the feeder setting section of each component mounter; and - a control device configured to control an operation of the automatic exchanging device, wherein when it is determined that a number of empty slots of the feeder setting section of any one of the component mounters is equal to or larger than a predetermined value based on a monitoring result of the feeder arrangement monitoring section, the control device controls the operation of the automatic exchanging device such that an automatically exchangeable unit is set in one of the empty slots of the feeder setting section of the component mounter; wherein the automatically exchangeable unit is a unit that can be automatically exchanged with respect to the one empty slot of the feeder setting section by the automatic exchanging device.