A method for manufacturing an ink-jet head includes the step of forming, in a substrate, through holes respectively corresponding to conductors on one face of the substrate and each having its diameter increasing from the one face toward the other face of the substrate. Here, the through holes are formed in such a manner as to satisfy R>d/2+t/tan .theta., where: d represents a width of an opening of the through hole on the one face; .theta. represents an angle of inclination of a sidewall defining the through hole with respect to the one face; R represents a shortest distance from the center of the through hole to a periphery of an electrode that neighbors an electrode corresponding to the through hole; and t represents a thickness of the substrate.