A method and an assembly device for automated determination of a drilling position of a drill hole for a fastener for fastening a component to a possible wall area of a wall, wherein the method steps include: determining a surface contour of the wall area; examining the surface contour and detecting first irregularities in the surface contour using a first detection rule; determining a primary possible support surface area and a primary possible drilling position area that do not have any of the detected first irregularities; examining the surface contour of the primary possible drilling position area and detecting second irregularities in the surface contour using a second detection rule; and determining the drilling position inside the primary possible drilling position area such that the surface contour at the drilling position does not have any of the detected second irregularities.