A head unit 103 for use in a droplet ejection apparatus is provided with a plurality of droplet ejection heads for ejecting one or more kind of liquid material of a predetermined color onto a base in the form of droplets. Each of the droplet ejection heads includes at least one nozzle array constituted from a plurality of nozzles linearly aligned. The liquid material is adapted to be ejected through the plurality of nozzles of the plurality of droplet ejection heads in the form of droplets. The plurality of droplet ejection heads for ejecting the liquid material of the same color are arranged so that the nozzle arrays of the plurality of droplet ejection heads are parallel to each other in a first direction and each of the plurality of droplet ejection heads partially overlaps at least one of the other droplet ejection heads when viewed from a second direction perpendicular to the first direction. All the plurality of droplet ejection heads for ejecting the liquid material of the same color which are partially overlapped each other eject the liquid material onto a predetermined region of the base in the form of droplets.