Aiming at direct ignition-timing control of homogeneous charge compression ignition in low-load conditions, pulsed flame jet, which is the jet of burning gas issuing from a small cavity facing a combustion chamber, was utilized. The characteristics of homogeneous charge compression ignition combustion initiated by pulsed flame jet were investigated using rapid compression expansion machine, which realizes single compression and expansion strokes and thus the measurement of indicated work. Higher indicated mean effective pressure was obtained using pulsed flame jet without increasing NOx emission drastically, and it was shown that pulsed flame jet has potential to control the onset of homogeneous charge compression ignition combustion appropriately. The validity of pulsed flame jet utilization was shown through pressure and NOx measurements.