We studied three groups for the evaluation of usefulness and normal range of Eustachian tube function test. The one group was 37 persons of 18 year old and the second were 17 persons of 12 year old and the third were 17 persons of adult. The tympanic membrane was intact and the resting middle ear pressure was normal. In the 18 year old age group, the scale of fatness was 94% and the mean weight was 65kg and the mean height was 167cm. The sensitivity of Valsalva test was 97% and the mean value was -30.4 daPa and the mean frequency was 1.6 times. The sensitivity of Toynbee test was 78% and the mean value was 77 daPa and the mean frequency was 1.6 times. The sensitivity of 9 step test in inflation phase was 47% and the mean value was -7.2 daPa. The sensitivity of 9 step test in deflation phase was 65% and the mean value was 15.6 daPa. The correlation between the fatness scale and the frequency, value, and sensitivity of the test was evaluated. Nothing was meaningful except the value of valsalva test. The p value was less than 0.05. In the 12 year old age group and adult group, only the 9 step test was done at 200 daPa and 400 daPa. The sensitivity of inflation test in 200 daPa was 18% and the sensitivity of deflation test in 200 daPa was 35%. The sensitivity of inflation test in 400 daPa was 24% and the sensitivity of deflation test in 400 daPa was 12%. The sensitivity of 9 step test was 73% in 18 year old age groups, 59% in 12 year old age group, 65% in adult.