In this paper, simulation of cutting edge wear rate model based on the chip production rate in micro-endmilling is conducted in order to understand the state of the interaction between the tool and the workpiece. In micro-endmilling, the chip production rate changes due to the cutting edge wear and it can be explained by the minimum chip thickness effect. If the cutting edge radius increases due to the tool wear until the minimum chip thickness becomes larger than the uncut chip thickness, the chips will not be generated with the cutting tooth sliding on the workpiece. If the new tool with the sharp cutting edge is used, the chips will be generated without the cutting tooth sliding on the workpiece. From this point of view, the cutting edge wear could be observed by measuring the chip production rate in micro-endmilling. Therefore, the cutting edge wear rate model is proposed and the simulation of the cutting edge wear rate estimation is conducted. Our proposed cutting edge wear rate model could be used in improving the tool life and the surface quality by estimating the cutting edge wear rate.