To provide a fluorescent temperature sensor wherein light is propagated reliably with an easy adjustment. A fluorescent temperature sensor for producing a temperature signal from fluorescent light of an optically excited fluorescent material includes: a light emitting device for projecting light to the fluorescent material; a photoreceiving element for receiving fluorescent light emitted from the fluorescent material 1; a case for housing both the light emitting device and the photoreceiving element; and an optical fiber, between the case and the fluorescent material, for propagating the light of both the light emitting device and the fluorescent material. The case and the optical fiber are positioned so that the light from the light emitting device is received within the optical fiber, and so that the light from the fluorescent material is incident on the photoreceiving element from within the optical fiber.