To provide a float floating and sinking depending on water temperature and having the function of showing of temperature exceeding a fixed value, although a float in water has only an interior ornamentation function conventionally.

A straw-shaped tube 2 is located within the float and a weight 3 is arranged around the tube. The quantity of the weight 3 is adjusted depending on the desire of a user that at what temperature the float is to float. When the temperature is lower than a temperature at which the float floats, the volume of air in the float body 1 is compressed to cause water to come in the tube while sinking the float body 1. When the temperature is at a fixed value or higher, the volume of air in the float body 1 is expanded to expel the water in the tube 2 while causing the float body 1 to float on the surface of water.