A method for manufacturing an ink jet head having a discharge opening for discharging ink and an ink passage communicated with the discharge opening, includes the step of forming the discharge opening by performing a cutting operation along a portion where the discharge opening is to be formed, while maintaining the ink passage in a pressurized condition by filling the ink passage with fluid. Another method includes the step of cleaning an ink passage by introducing liquid and gas into the ink passage alternately; and an ink jet apparatus comprising such an ink jet head, and a member for holding the ink jet head.