PURPOSE: To stabilize ink discharge characteristics, to improve the grade of printing, to prevent the generation of noises and to obviate the shortening of the lifetime of a head.

CONSTITUTION: A substrate 1, to which a large number of pressure chambers 2a-2n radially juxtaposed from a rectilinear central end section, common ink paths 3 surrounding each pressure chamber and communicating with the pressure chambers 2a-2n, and ink introducing ports supplying the common ink paths 3 with ink are formed, nozzles 5 formed while penetrating the substrate 1 at the rectilinear central end sections of each pressure chamber 1, and mounting diaphragms 6 on the pressure-chamber forming surfaces of the substrate 1 are provided. In an ink-jet printing head, in which a piezoelectric type head unit with piezoelectric elements 7a-7n set up to the diaphragms 6 in response to each pressure chamber 2a-2n and flexible cables 8 connecting each of each piezoelectric element 7a-7n to a signal generating source is incorporated into a base 10, support sections 9a supporting the positions of the diaphragms 6 corresponding to the central end sections including the nozzles 5 are provided.