A mounting device for performing an assembly process in an elevator shaft of an elevator system includes a support component and a mechatronic assembly component. The support component moves within the elevator shaft. The assembly component is retained on the support component and carries out a mounting step in an at least partially automatic manner during the assembly process. The support component includes a fastening part that secures the support component and/or the assembly component in a direction extending transversely to the vertical, i.e. for example in a horizontal or lateral direction, within the elevator shaft.