To provide a device capable of measuring a temperature and a humidity accurately.

This temperature/humidity measuring device 1 is equipped with a body 10 equipped with a liquid crystal panel 11 for display on the surface, and a sensor 20 connected to the body 10 through a connection cord 21, for storing a temperature measuring element and a humidity measuring element. The temperature/humidity measuring device 1 can measure the change of the temperature and the humidity in the environment where the sensor 20 is installed, and display the result on the same liquid crystal panel 11. When water leakage occurs, the sensor 20 can be replaced easily, and highly accurate measurement can be always performed by a normal sensor.