To provide a temperature detecting element of high temperature followability in a high temperature area.

Heat of gas is received by a heat receiving member 11 arranged faced to a temperature measuring area of the gas in a cylinder and formed into a thin shape, a thickness-directional displacement is generated by a temperature change therein, the displacement in the heat receiving member 11 is transmitted to a diaphragm 12c of a deformation generation part 12 by a transmission member 13, and a deformation of the diaphragm 12c is detected by a strain detecting element 14. A temperature of the gas is detected based on the deformation of the diaphragm 12c detected by the strain detecting element 14. The heat receiving member 11 indicates a temperature change following the temperature change of the gas, because formed into the thin shape and having a low heat capacity, to generate the thickness-directional displacement. The temperature detecting element 10 of high temperature followability, in particular, in the high temperature area, is provided because the temperature change is detected based on the displacement.