A temperature sensor element 10 has a reduced thermal conduction path from a measurement object to a sensitive end portion 22 of a thermocouple 21 and a high-dense insulating ceramic base body 20. Since the temperature sensor element 10 has excellent thermal conductivity from the measurement object to the sensitive end portion 22 of the thermocouple 21, it is also excellent in responsiveness at the time of temperature detection. Further, corrosion and material deterioration of the thermocouple 21 is unlikely to occur because the thermocouple 21 does not directly contact the measurement object (exhaust gas). As a result, the temperature sensor element 10 exhibits excellent durability. Therefore, the temperature sensor element 10 exhibits a good responsiveness at the time of temperature detection as well as excellent durability.