In the Japanese construction industry, it is predicted that during the next ten years, more than a million veteran technicians will retire, and a sudden shortage of experienced technicians will be inevitable. One way of countering this problem now being considered is the use of robotics technology to support inexperienced operators. To develop such systems, it is important to first quantitively compare differences of the working efficiency, working quality, operating methods etc. between experienced operator and inexperienced operator. Hence, experiments were performed to compare how experienced operators and inexperienced operators execute base course material grading work using a motor grader. During the experiments, the time required to complete the work, and the finished height at a pitch of 1 m were measured in order to quantitatively identify working efficiency and working quality. To clarify operating methods, the line of sight of the operators during work was measured. Moreover, similar comparative experiments were performed with the introduction of MC to verify its impact on experienced and inexperienced operators.