A body temperature measuring device (1) that is non-electric and non-contact, capable of measuring body temperature with high accuracy, and capable of easily increasing the accuracy of body temperature measurement by upgrading the software is provided. A body temperature measuring device (1) includes a body temperature detecting unit (11) and a terminal device (10). The body temperature detection unit 11 includes a power supply unit 11b that converts an audio output signal from the terminal device 10 into electric power, a detection unit 11c that detects infrared energy from the user's skin surface as a temperature detection signal, and the temperature detection signal. Is converted to an audio input signal. The terminal device 10 calculates oscillation means for oscillating an audio output signal to the body temperature detection unit 11, an audio input signal received from the body temperature detection unit 11, the emissivity of the skin surface of the user, and calculation within a predetermined measurement time. Measuring means for estimating the surface temperature of the small change amount as the body temperature of the user based on the change amount of the surface temperature with time.【課題】無電地式で、且つ、非接触式で、精度高い体温測定を可能とし、ソフトウェアのバージョンアップにより体温測定の精度アップを簡単に実施することが可能な体温測定装置１を提供する。【解決手段】体温検知部１１と端末装置１０とより構成される体温測定装置１である。前記体温検知部１１は、前記端末装置１０からの音声出力信号を電力に変換する電源部１１ｂと、ユーザの皮膚表面からの赤外線エネルギーを温度検知信号として検知する検知部１１ｃと、前記温度検知信号を音声入力信号に変換する変換部１１ｄとを備える。前記端末装置１０は、前記体温検知部１１へ音声出力信号を発振する発振手段と、前記体温検知部１１から受信した音声入力信号と前記ユーザの皮膚表面の放射率と所定の測定時間内に算出された表面温度の経時的な変化量に基づいて前記変化量が小さい表面温度を前記ユーザの体温として推定する測定手段とを備える。
