This paper is concerned with determination of sampling frequencies for digital control of servo system such as industrial robots and industrial machines. Recently, digital control of servo system has been widely accepted in industrial fields. However, delay time caused by computational time of the digital control causes deterioration of control performances if the sampling frequency of the sampler is not appropriate one. We had proposed a method for a requisite sampling frequency for a single sampler system. The result was derived based on theoretical background and gave a reasonable one. We further developed the previous work of the sampling frequency. In this study, we investigated the determination of two sampling frequencies for position loop and velocity loop of multi-samplers servo system. The problem was analysed in S plane, but not in Z plane, then the derivation of the formula for appropriate sampling frequencies was successful. By using the formula and the given system parameters of an equipment such as gains, we can obtain appropriate sampling frequencies for position loop and velocity loop of the servo system easily. The obtained results were evaluated by an experiment with a personal computer of digital controller and analog computer of simulated servo system. We obtained satisfactory experimental results of sampling frequencies. The proposed method for determination of sampling frequencies will be applicable widely in industrial fields to determine the sampling frequencies of the digital servo systems.