A flux applying device for applying flux to a surface of long strip -like solder, the flux applying device comprising: a dipping means that applies the flux to the surface of the solder by dipping the solder into the flux; a load applying means that applies a predetermined load to the solder, the load applying means being provided at an upstream side of the dipping means, when a side into which the solder enters is set to be the upstream side and a side out of which the solder is discharged is set to be a downstream side; a constant speed conveying means that conveys the solder at a predetermined speed, in a state where a load is applied by said load applying means, the constant speed conveying means being provided at a downstream side of the dipping means, the solder to which the flux is applied by the dipping means being pulled up vertically in relation to a liquid surface of the flux; and being characterised by: a drying means that dries the solder to which the flux is applied, the drying means being provided at the downstream side of the dipping means; a cooling means that cools the dried solder; a conveying speed measurement means that measures a conveying speed of the solder; a control means that controls the conveying speed of the solder based on the measurement result of the conveying speed of the solder by the conveying speed measurement means; a flux applying chamber that houses at least the dipping means, the drying means, and the cooling means; wherein said chamber includes a discharging means that communicates with the outside of the flux applying chamber and discharges hot air and the volatilized solvent contained in the flux inside the flux applying chamber. a dipping means that applies the flux to the surface of the solder by dipping the solder into the flux; a load applying means that applies a predetermined load to the solder, the load applying means being provided at an upstream side of the dipping means, when a side into which the solder enters is set to be the upstream side and a side out of which the solder is discharged is set to be a downstream side; a constant speed conveying means that conveys the solder at a predetermined speed, in a state where a load is applied by said load applying means, the constant speed conveying means being provided at a downstream side of the dipping means, the solder to which the flux is applied by the dipping means being pulled up vertically in relation to a liquid surface of the flux; and being characterised by: a drying means that dries the solder to which the flux is applied, the drying means being provided at the downstream side of the dipping means; a cooling means that cools the dried solder; a conveying speed measurement means that measures a conveying speed of the solder; a control means that controls the conveying speed of the solder based on the measurement result of the conveying speed of the solder by the conveying speed measurement means; a flux applying chamber that houses at least the dipping means, the drying means, and the cooling means; wherein said chamber includes a discharging means that communicates with the outside of the flux applying chamber and discharges hot air and the volatilized solvent contained in the flux inside the flux applying chamber. a drying means that dries the solder to which the flux is applied, the drying means being provided at the downstream side of the dipping means; a cooling means that cools the dried solder; a conveying speed measurement means that measures a conveying speed of the solder; a control means that controls the conveying speed of the solder based on the measurement result of the conveying speed of the solder by the conveying speed measurement means; a flux applying chamber that houses at least the dipping means, the drying means, and the cooling means; wherein said chamber includes a discharging means that communicates with the outside of the flux applying chamber and discharges hot air and the volatilized solvent contained in the flux inside the flux applying chamber.