In MEC, there is a possibility that the processing time will increase or the blocking rate of jobs in the edge server will increase due to the concentration of job processing requests in the edge server. To solve this problem, we propose a threshold-based job control method that satisfies the blocking rate required by the system for real-time jobs and minimizes the blocking rate for non-real-time jobs. In this paper, we show that the optimal threshold value can be set by using queueing theory, and analyze the characteristics of the proposed method.