In a head part of inkjet printer, a leading droplet and a following droplet are ejected from an outlet by inputting one driving signal, and the leading droplet and the following droplet land onto a recording paper. At this time, a waveform of the driving signal is set such that an average of distance from the center of a main dot element formed by the leading droplet to the farthest point in a group of dot elements formed by the leading droplet and the following droplet is equal to or more than 1.1 times an average of radius of the main dot element and equal to or less than 3.0 times the average. Therefore, the dot shape can be made noncircular, and as the result, it is possible to suppress jaggies on edges of an image on the recording paper and lowering of density in a solid area.