In the real production functioning of the cutting tool takes place in the conditions of properties dispersion of the technological system elements that defines stochastic character of the cutting process parameters. As a result casual character has a basic data-out of cutting process - the cutting tool life. It is presented the method of the cutting regimes optimization taking into account the variation coefficient and the distributing law of the cutting tool life as casual value. The analysis of the optimization criteria (productivity and prime price) as functions of casual argument - the cutting tool life is executed. There are got analytical dependences, which allow taking into account dispersion of the cutting tool life at determination of its optimum value. There are set the correction coefficient on the productivity and prime price optimum cutting speeds taking into account the coefficient of cutting tool life variation. There are set the necessary for providing of the set level of reliability the coefficient of the cutting regimes change.