The article addresses the automation of the resistance bridge calibrator (RBC). The automation of the RBC is performed in order to facilitate the operation of the RBC, improve the reliability, and enable several additional possibilities compared to the tedious manual operation, thereby making the RBC a more practical device for routine use. The RBC is used to calibrate AC and DC resistance bridges, which are mainly used in a primary thermometry laboratory. It consists of a resistor network made up from four main resistors from which 35 different resistance values can be realized using toggle switches. Literature shows that the resistors’ non-zero temperature coefficient can influence the measurements, causing difficulties when calibrating resistance bridges with low uncertainty. Placing the RBC in a thermally stable environment can reduce this, but it does not solve the problem of the time-consuming manual selection of the resistance values. To solve this, an automated means to manipulate the switches, while the device is placed within a thermally stable environment, was created. Computer operation completely substitutes for any manual operation during which an operator would normally have to be present. The computer also acquires measurements from the bridge. In this way, repeated and reproducible calibration measurements inside a temperature-stable environment can be carried out with no active involvement of personnel. The automation process itself was divided into several stages. They included the construction of a servo-manipulator to move the switches, the design of a dedicated electronic controller that also provides a serial interface (RS-232) to the computer, and the development of custom computer software to configure the servo-manipulator and control the calibration process. Measurements show that automation does not affect the long-term stability and mechanical repeatability of the RBC. The repeatability and reproducibility of bridge calibration ratios were also demonstrated by making consecutive measurements.