An ink jet recording apparatus comprises: at least one ink jet head to emit a recording ink; main and sub ink tanks to store the ink which should be supplied to the head; a negative pressure generating device to generate a negative pressure to supply the ink from the sub ink tank into the head under the suction action; a pressure sensor, provided in the ink passage, for detecting whether the recording ink substantially remains or not in the sub ink tank when the negative pressure generating device operates. In response to a pressure variation in the ink passage, the pressure sensor determines that no ink substantially remains in the sub ink tank when the pressure in the ink passage is higher than a preset value, thereby generating a detection signal to supplement a new ink into the tank to a control circuit. Therefore, the absence of ink in the tank can be certainly detected and the ink can be emitted in good conditions, so that the recording can be smoothly performed by a simple, cheap and small-sized apparatus.