PURPOSE: To exchange a head in a stopped state of injection easily by providing a pressure generating section of an ink jet head detachably from the top of a pressure chamber.

CONSTITUTION: An ink jet head 1 comprises a head 1a and pressure generating sections 10A, 10B. An auxiliary vibrating plate 7 is provided covering a pressure chamber 4 for generating pressure for ejecting ink drips. The pressure generating sections 10A and 10B are arranged detachably on the auxiliary vibrating plate 7. The pressure generating section 10A is formed integrally with a carriage 16 and the pressure generating section 10B is supported movably by the carriage 16 through a pin 22. The head 1a is arranged between the pressure generating sections 10A and 10B so as to close the pressure generating section 10B and to be clamped by the pressure generating sections 10A and 10B. A recording by the ink jet head 1 is performed in a state that the head 1a is clamped. When the head is to be exchanged in a stopped state of the injection, the pressure generating section 10B is opened so that the head 1a can be exchanged easily.