The invention provides a temperature sensing device. The temperature sensing device comprises a sensing head base, a sensing head body part, a simulated blackbody cavity, a high-temperature optical system, a high-temperature-resistant optical fiber, an optical fiber fixing structure, a fixing jackscrew, a light transmission optical fiber and a signal processing system. The simulated blackbody cavity is arranged in the sensing head base; the high-temperature optical system is used for collecting an optical radiation signal emitted by the simulated blackbody cavity; the high-temperature-resistant optical fiber is used for receiving the optical radiation signal collected by the high-temperature optical system; the optical fiber fixing structure is used for fixing the high-temperature-resistant optical fiber; the fixing jackscrew is used for limiting movement of the optical fiber fixing structure in the axial direction of the sensing head body part; the light transmission optical fiber isconnected with the high-temperature-resistant optical fiber; and the signal processing system is used for converting the optical radiation signal outputted by the light transmission optical fiber intothe temperature of an object to be measured. According to the technical scheme, the technical problems that in the prior art, the temperature measuring range of a temperature sensing device is limited, and dynamic response, interference shielding, service life and severe environment adaptability are poor are solved.