To provide an ink-jet print head which is improved in printing speed, and to provide an ink-jet print head operating method.

The ink-jet print head is comprised of a chamber layer (a) which is formed of an ink via 2, a plurality of ink chambers 3 inclusive of respective heaters 5, and ink channels 4 connecting between the ink via 2 and the respective ink chambers 3; and a nozzle layer (b) which is formed of a plurality of nozzles 6 so as to correspond to the respective ink chambers 3. Each ink channel 4 includes a multi-functional structure 7 defined by two mutually opposed walls extending from the ink chamber 3 to the ink via 2.