Necessity of life insurance is stronger for people who feel some anxiety of their health. However, in fact, it is not permitted for them to get a contract, because life insurance stands on the mutual benefit system. Life insurance must be impartial to all applicants. However, it is very reasonable that an applicant, who has high medical impairment like heart infarction or cancer, is rejected, to have a contract by underwriting decision. On the other hand, if his medical impairment is not so severe, we might accept his application by giving some restriction. Numericalratingsystem by hunter-rogers gave us one of solutions to this problem. We can keep impartiality by using more restrictive decision, in order that we demand additional payment to the impairment applicant according to his mortality. We call this system as substandard life insurance. In this system we need detail information about impairments of applicants in order to decide the condition of substandard risks. Therefore, medical examiners are required to have high diagnostic technique.