The master's thesis was focused on a detailed study of the mechanical structure-borne noise during the operation of the electric actuator. First the theory of sound waves was discussed and later used in the purpose-designed experimental methodology. For the purposes of gathering and processing of the sound signal a custom code was developed in open source program. The code enables the characterization of the structural noise of the actuator unit in time and frequency domain. That was followed by the defining of the methodology for sample preparation in order to ensure the reliability, repeatability and comparability of the measurements. Based on the analysis of the subsets the 10 parameters were selected. They were used to identify the critical sources of noise from the viewpoint of the sound power level of the whole actuator unit. Mutual comparison of the results highlighted the most influential parameters.