The invention belongs to a self-adjusting fixed value resistor device, and relates to the field of electronic engineering. The invention aims to provide the self-adjusting fixed value resistor device.In order to achieve the purpose, the non-add-and-subtract position of a moving contact in the resistance adjusting device is located near a midpoint position between a minimum resistance value and amaximum resistance value. The self-adjusting fixed value resistor device also comprises a device used for receiving and storing an output voltage upper limit value and an output voltage lower limit value which are input manually. The self-adjusting fixed value resistor device also comprises an automatic control device with the following functions: firstly, the voltage of a sampled electric signalis compared with the output voltage upper limit value and the output voltage lower limit value which are input manually so as to obtain difference values; secondly, the electric signal is monitored and sampled in real time at the position of a specific point in the circuit; and thirdly, the moving contact of the automatic control resistance adjusting device in the related circuit moves leftwards at a specific distance, moves rightwards at the specific distance or move to the non-add-and-subtract position. The device has the beneficial effects that a constant resistance value can be maintained.