PROBLEM TO BE SOLVED: To provide a thermometer and a temperature measuring method capable of resolving effect of heat balance that is actualized by miniaturizing a sensor.SOLUTION: A thermometer comprises: a base material with a surface of 1 arranged on a boundary surface between a first medium and a second medium； a first temperature measuring part 20 for measuring, as a first temperature, a temperature of a first position of the base material； a second temperature measuring part 22 for measuring, as a second temperature, a temperature of a second position having a thermal resistance value between the first position and the second position； a medium temperature measuring part 24 for measuring, as a medium temperature, a temperature of the first medium or the second medium surrounding a base material where the first temperature measuring part 20 and the second temperature measuring part 22 are arranged； an enclosure body arranged on the first medium or the second medium surrounding the base material where the first temperature measuring part 20 and the second temperature measuring part 22 are arranged； an internal medium where the base material of the enclosure body is arranged and its inside is full； and a calculation part 36 for calculating an internal temperature of the first medium or the second medium as a deep temperature by using the first temperature, the second temperature, and the medium temperature.【課題】センサーの小型化によって顕在化する熱収支の影響を解決することができる温度計及び温度計測方法を提供する。【解決手段】第１媒体と第２媒体との境界面に１の面を配置した基材と、基材の第１位置の温度を第１温度として測定する第１温度測定部２０と、第１位置との間に熱抵抗値を有する第２位置の温度を第２温度として測定する第２温度測定部２２と、第１温度測定部２０と、第２温度測定部２２を配置した基材とを取り巻く第１媒体又は第２媒体の温度を媒体温度として測定する媒体温度測定部２４と、第１温度測定部２０と、第２温度測定部２２を配置した基材を取り巻く第１媒体又は第２媒体に配置した外郭体と、外郭体の基材を配置した、内部を満たす内部媒体と、第１温度と、第２温度と、媒体温度とを用いて、第１媒体又は第２媒体の内部の温度を深部温度として演算する演算部３６と、を含む。【選択図】図１
