There is provided a flux applying apparatus configured to jet and apply a flux to a target, whereby the flux applying apparatus is capable of rapidly collecting a surplus flux in a sub-tank and returning the same to the main tank for further jetting and applying. In particular, the flux applying apparatus is coupled to a control unit capable of estimating a flux amount trapped in the sub-tank on the basis of a time period for which the flux is to be jetted from the nozzle.