Manufacturing method of liquid ejection head

A manufacturing method of a liquid ejection head that is a method for reusing a first head chip of a first liquid ejection head to manufacture a second liquid ejection head including the first head chip and a second head chip different from a head chip incorporated in the first liquid ejection head, the first head chip and the second head chip each including an actuator that is driven for liquid ejection, the manufacturing method comprising:

• a removal step of removing the first head chip from the first liquid ejection head;
• an assembly step of incorporating the first head chip into the second liquid ejection head;
• and
• an adjustment step of performing an adjustment process of reducing a difference between ejection performance of the first head chip and ejection performance of the second head chip, on the actuator of at least one of the first head chip or the second head chip.