Provided are a component replenishment support method, and a component replenishment support system of a component mounting line that are capable of preventing a decrease in facility operation rate due to component shortage, in which a component shortage time of each part feeder is predicted, a component replenishment work is started from the present time in a case where the component shortage time is earlier than the virtual work end time, a work end time of the work target selection feeders in sequence of early time by using the part feeder within the warning consideration start time as a target is predicted, and a worker is warned of the component replenishment to the selection feeder of which the work end time is within the warning start time, in a case where the selection feeder of which the component shortage time is earlier than the work end time is not present.