The parameters were analyzed which decided the optimization on designing the machine tools having the minimum chance of regenerative chatter by means of the computer program system. These parameters are the modal flexibility and the logarithmic decrement, and their influences on dynamic characteristics are completely different. The macroscopic analysis is needed to carry out the optimization. First of all, the ratio of the modal flexibilities to the static compliance at the cutting point should be analyzed, which indicates the balance of the receptances among all resonance modes, in order to detect the resonance modes having the possibility of the regenerative chatter, and these values should be optimized. After it is understood that the values of the modal flexibilities and the ratios to the static compliance are reasonable, the optimization with respect to the damping characteristics should be carried out. The instability of the regenerative chatter is judged, to be exact, by the maximum real negative part of the compliance on the vector loci. Therefore, the parameters to move vector loci along the real axis on the polar coordinate were investigated. It was denoted that the distribution of the modal flexibility through all frequency range was very important.