To provide a pattern forming device in which use efficiency of a laser beam for drying drops during flight is increased and energy for drying that each drop receives during flight is leveled.

The pattern forming device is designed such that a center interval of the drops D ejected from a nozzle line NL having a plurality of nozzles located at a nozzle pitch Dx corresponds to a YL pitch YLd in a transverse direction (+YL direction) with respect to the advancing direction LL of a first laser beam Le1. The YL pitch YLd consists of a drop diameter Di of a drop D and a laser passing space width L. The laser passing space width L corresponds to a distance in which the intensity of the laser beam diffracted and attenuated with vibration by diffraction surfaces Da of the drops D on the front side in the advancing direction is in the course of being static according to increase in distance toward the +YL direction. In other words, the advancing direction LL is given with respect to the nozzle line NL so that the YL pitch YLd is assured in the +YL direction. Thus, an inclination angle between the advancing direction LL thus given and the nozzle line NL is selected in a range of satisfying the relation sinYLd/Dx.