A paint filling apparatus has a plurality of header portions, and one common manifold portion that is capable of supplying a cleaning liquid to each header portion. One side of each header portion is attachable to and detachable from a paint cartridge, and another side of each header portion is attachable to and detachable from the common manifold portion. Each header portion has a paint supply channel for filling a paint into the paint cartridge. The paint supply channel of each header portion is constructed of a piping member and a paint channel. An end portion of each header portion is linkable in communication with the inside of the paint cartridge, and another end portion thereof is linked in communication with a corresponding one of paint tanks that are provided separately for each of the paint colors. An intermediate portion of each paint supply channel is provided with a paint valve that controls the open-closed state of the upstream side of the paint supply channel.