This paper presents the efficacy of our evolutionary clinical electrical thermometer that fixes a soft material ball over a tip of a temperature probe to fit an axilla of him/her. The soft material ball allows them to hold the temperature probe more easily with weak power without causing deviation in a position of it in the axilla. However, it is much harder to measure an axillary temperature in a short time with the soft material having thermal conductivity and capacity worse. We have developed therefore a temperature prediction mechanism that makes it possible to mathematically calculate an axillary temperature. In this paper, we aim to verify the efficacy of our evolutionary clinical electrical thermometer by comparing the error between measured value and predicted value in the axillary of him/her. As a result, the prediction error is 0.15 ± 0.16 oC, and 253.5 ± 12.5 seconds is denoted the prediction time.