Abstract: A soldering apparatus comprises at least one soldering iron (19) with a heating element (21) and a regulating circuit including a temperature sensor (22) for regulating the working temperature of the soldering iron (19) to a predeterminable desired value (51). The apparatus is characterized by a circuit (45) connected to the soldering unit (19) which at least temporarily stores values corresponding to a time-dependent temperature plot for the soldering iron (19), and also by a monitoring circuit (14) which is connected to the memory circuit. The monitoring circuit monitors during the operation of the soldering iron, from the stored values for the temperature plot, determines whether the temperature undergoes an excursion beneath or above predeterminable upper and lower temperature limits (52, 53) and initiates an alarm signal when the duration of the excursion exceeds a predetermined value.