A paint filling apparatus that fills a paint cartridge with a paint of a color selected from a plurality of color paints, comprising: a plurality of header portions; wherein: one side of each of the header portions is attachable to and detachable from the paint cartridge; each header portion is provided with a paint supply channel for filling the paint into the paint cartridge; one end portion of the paint supply channel of each header portion is linkable in communication with an inside of the paint cartridge, and another end portion of each paint supply channel is linked in communication with a corresponding one of a plurality of paint supply sources that are provided separately for each of the colors of the paints; and an intermediate portion of each paint supply channel is provided with a paint valve that controls an open-closed state of an upstream side of the paint supply channel; characterized in that the paint filling apparatus further comprises: one common manifold portion that is able to supply a cleaning liquid to each of the header portions, wherein: another side of each header portion is attachable to and detachable from the common manifold portion. a plurality of header portions; wherein: one side of each of the header portions is attachable to and detachable from the paint cartridge; each header portion is provided with a paint supply channel for filling the paint into the paint cartridge; one end portion of the paint supply channel of each header portion is linkable in communication with an inside of the paint cartridge, and another end portion of each paint supply channel is linked in communication with a corresponding one of a plurality of paint supply sources that are provided separately for each of the colors of the paints; and an intermediate portion of each paint supply channel is provided with a paint valve that controls an open-closed state of an upstream side of the paint supply channel; characterized in that the paint filling apparatus further comprises: one common manifold portion that is able to supply a cleaning liquid to each of the header portions, wherein: another side of each header portion is attachable to and detachable from the common manifold portion. one side of each of the header portions is attachable to and detachable from the paint cartridge; each header portion is provided with a paint supply channel for filling the paint into the paint cartridge; one end portion of the paint supply channel of each header portion is linkable in communication with an inside of the paint cartridge, and another end portion of each paint supply channel is linked in communication with a corresponding one of a plurality of paint supply sources that are provided separately for each of the colors of the paints; and an intermediate portion of each paint supply channel is provided with a paint valve that controls an open-closed state of an upstream side of the paint supply channel; characterized in that the paint filling apparatus further comprises: one common manifold portion that is able to supply a cleaning liquid to each of the header portions, wherein: another side of each header portion is attachable to and detachable from the common manifold portion. one common manifold portion that is able to supply a cleaning liquid to each of the header portions, wherein: another side of each header portion is attachable to and detachable from the common manifold portion. another side of each header portion is attachable to and detachable from the common manifold portion.