An ink jet head for discharging ink comprises a plurality of elemental substrates having a plurality of discharge energy generating elements arranged in line for discharging ink, a grooved member having a plurality of walls joined with the plurality of elemental substrates arranged to constitute ink paths for each of the discharge energy generating elements, these ink paths being formed by joining the walls of the grooved member under pressure with the plurality of elemental substrates thus arranged, and among the plurality of walls, a plurality of ribs formed on the bottom of each wall arranged on each boundary between elemental substrates, and configured along this boundary line to abut upon each of different elemental substrates, respectively. In this way, any gaps and steps existing between the elemental substrates are sealed by the ribs formed for the walls of the grooved member when this member is joined with the elemental substrates under pressure, thus preventing any ink leakage from such gaps or steps, and also, suppressing the pressure wave cross talk between ink paths in order to perform recording in good condition.