This paper examines the ratio of those who gain the unemployment allowance to the total unemployed population in Japan. This paper also looks at the possible backgrounds which affect the unemployment ratio in the case where the ratio decreases. By far, several studies have calculated the ratio but the previous method is said to exaggerate the figure. This paper proposes a new method to calculate that ratio on a more reliable basis. According to our calculation, the rate is around 20%, the figure of which was far smaller than the figure given in previous studies. We also found four factors which affect the ratio. As for the male unemployed, the cause of decrease in the ratio was due to the fact that the average duration of the allowance payment was shortened even though the average duration of unemployment became longer compared with the past.