PURPOSE: To prevent the ink pressure of a pressurizing ink jet recorder from rising excessively by providing a means which operates in response to a pressure higher than a set value so that it releases the ink pressure at the ink flow route between a pump and the ink jet nozzle of the recorder.

CONSTITUTION: Ink pressurized by a pump 3 is supplied to a sheet of recording paper 13 from an ink jet head 8 through an electromagnetic switching valve 5, a filter 6 and a heater 7. When the pressure of ink rises abnormally, the input port of the electromagnetic switching valve 5 is caused to interconnect with an ink receptacle 16 and ink is accumulated in the ink receptacle 16. By this, a current flows through between a metal disk 161 and a solenoid rod 163 and causes a buzzer to sound.