Abstract: An agitator of washing machine has a washing shaft installed on a lower portion of a washing tub and extending upward to a bottom of the washing tub to be installed rotatively. A driving cam is installed on the washing shaft to rotate integrally with the washing shaft. A driven cam is installed around the washing shaft and contacts a surface of the driving cam to be driven by rotation of the driving cam. A moving bar of which one end contacts an outer surface of the driven cam and the other end extends upward into the washing tub through a hole formed on the bottom of the washing tub is provided such that the other end of the moving bar moves rotatively in the washing tub by rotation of the driven cam. A plate for forming rotating water flows which is formed in the other end of the moving bar moves rotatively integrally with the moving bar, thereby forming the rotating water flow flows in the washing tub. And, an elastic means tightly pushes the one end of the moving bar onto the surface of the driven cam.