Ear temperature gun mainly uses the tympanic membrane infrared radiation principle to measure body temperature, while the mercury thermometer is mainly used to measure the temperature of the armpit, mouth, anus, measuring different parts, the measured body temperature varies slightly, but usually the difference does not exceed 1 ℃. Ear temperature gun to measure the normal body temperature is 35.8 ℃ -38 ℃, more than the normal temperature of 0.5 ℃ is considered fever. The standard body temperature of mercury thermometer is 36.0-37.0℃ for axillary measurement, 36.3-37.2℃ for oral measurement, and 36.5-37.7℃ for anal measurement. Ear temperature gun temperature measurement is fast, easy to carry, not easy to break, but when using it, we should pay attention to the best each time with a new outer mold set, before measurement need to avoid exposure to the sun or exercise, measurement is best to measure two ears or a separate ear measurement 3 times, take its highest value, the gun head should be as deep as possible, but not to cause discomfort. In fact, when using an ear temperature gun to measure body temperature, the results can be affected by incorrect posture, cerumen, and moisture in the ear canal.