In the internal combustion engine such as diesel engine, the combustion performance is strongly affected by the fuel spray characteristics. Especially, the disturbance of liquid now inside the spray nozzle due to cavitation may contribute to the disintegration of the liquid jet outside the nozzle. The objective of the present study is to investigate the effect of the nozzle dimensions (nozzle length L / nozzle diameter D) on the liquid breakup. It was confirmed that the cavitation bubbles in the nozzle passage promote the atomization of liquid jet in case that L/D is 3.