In recent years, improvement of customer quality and added value is seen due to differentiation of producing place, farm, the roasting method of beans, grinding method, brewing method. In the modern coffee grinder and extraction method, the fluctuation of the taste after final grinding by each machine and each person was large, and the water contact area of powders after grinding changed. Reproducibility of taste is considered a problem in some coffee chain stores. In the study of the conventional coffee, there are many types of researches on the relation between the degree of roasting and the particle size and the relation of the taste, and no research on the extraction of the same taste has been conducted. In this paper, we focus on the grinding method of the coffee grinder and aim to make powder particle size distribution constant. Finally, as a result of comparing the current control simulating the grinding of the conventional mechanism using the full-wave rectified DC motor with the speed control introducing the servo mechanism of this mechanism, the speed control has a smaller speed error and a higher accuracy. In addition, by comparing the correlation coefficient between the conventional mechanism and this mechanism, the variance of the particle size was improved.