Abstract: A method and apparatus for measuring the surface temperature of a glass ampul which allows for the temperature to be determined as a function of time. The apparatus utilized is a thermocouple with the lead wires directly secured to the inside or outside surface of the glass ampul. Contact is assured by utilizing a high-temperature-resistive cement to secure the measuring function to the glass surface. To assure accurate temperature measurement, the lead wires are of a thin type and are uninsulated. The thermocouple wires opposite their junction are secured to a connector and ultimately to a thermocouple amplifier. If desired, a recorder is operatively connected to the amplifier. The temperature measuring apparatus allows for a constant temperature reading as the ampul is sterilized in a sterilizer and thus assures that complete sterilization is effected.