An inkjet head unit capable of performing high-resolution pixel printing on a large-size substrate and a substrate treatment apparatus including the inkjet head unit are provided. The substrate treatment apparatus includes: a processing unit supporting and moving a substrate; an inkjet head unit performing pixel printing on the substrate; and a gantry unit moving the inkjet head unit over the substrate, wherein the inkjet head unit includes head packs, which include a plurality of nozzles ejecting a substrate treatment liquid onto the substrate, and a head base, in which the head packs are installed and the head packs are disposed in a single row in the head base.