A fastening apparatus having a base part (4) for fastening and/or adjusting a light grid housing (1) having a partly round housing cross-section (34) in a housing section at an assembly body (12), wherein the base part (4) has an open receiver (24) for the light grid housing (1), wherein the receiver (24) forms a circular section (30) in cross-section and the circular section (30) has an angle (α) of more than 180 degrees, wherein the receiver (24) of the base part (4) is slightly smaller than the partly round housing cross-section (34) of the housing section, wherein the light grid housing (1) is arranged in the receiver (24) and is held by the receiver (24) by force transmission.