A deposition system, includes: a reaction chamber; a first gas supply unit supplying a first precursor in a liquid state stored in a first main tank to the reaction chamber in a gaseous state; a reactant supply unit supplying a reactant to the reaction chamber; and an exhaust unit discharging an exhaust material, wherein the first gas supply unit includes a first sub tank, a first liquid mass flow controller, and a first vaporizer, the first precursor is supplied to the reaction chamber by passing through the first sub tank, the first liquid mass flow controller, and the first vaporizer, a first automatic refill system operates to periodically fill the first sub tank with the liquid first precursor stored in the first main tank, and the exhaust unit comprises a processing chamber, a pump, and a scrubber to which a plasma pretreatment system is applied.