A temperature sensor for radiant heating units with a heating coil disposed in a cup includes a tube with a first end connected to a housing of a switch with a movable contact cooperating with stationery contacts in the housing. A two-section rod, which extends into the housing of the switch and operates the movable contact, is supported inside the tube. The tube and the rod have different thermal expansion coefficients. To prevent a shift in the switching point, the section of the rod that operates the contact terminates outside the hollow space of the cup, and the temperature-induced length changes of this section and of the housing are matched to each other.