Fastening device for a drive rod fitting component (1) which can be fixed in a groove (12) of a window or door sash by means of a clamping device (13), wherein the clamping device (13) comprises: - a housing (2) that guides the drive rod (5, 6) of the drive rod fitting component (1), wherein the housing (2) has at least in a foot (14) facing the groove base (15) a width which is less than the clear distance (16) between two opposing edge strip webs (17, 18) of the groove (12), - at least one adjustable clamping element (19), wherein the clamping element (19) is recessed behind the longitudinal edge (20, 21) of the housing (2) in a first inactive position and projects in front of the longitudinal edge (20, 21) of the housing (2) in a second active position and engages behind at least one edge strip web (17, 18), wherein the clamping element (19) is a plate (26) pivotably mounted in the housing (2), characterized by that the plate (26) has two parallel side edges (27, 28) which each terminate at right-angled transverse edges (29, 30) of the narrow sides, which open into clearances (31, 32) oriented inclined to the side edges (27, 28) and the transverse edges (29, 30), wherein a bore (34) is provided in the transition area (33) of a clearance (32) to the side edge (28), the plate (26) sits in a flat pocket (9) of the housing (2), the pocket (9) is open on both sides of the case (2) and has two stop edges (37, 38) inclined towards the longitudinal edges (20, 21) of the case (2), the housing (2) supports a slide (36) which can be moved along the length of the housing (2), the slider (36) engages the plate (26) and this moves the plate (26) in the pocket (9), so that the plate (26) abuts the edges (39, 40) in order to be pivoted against them until the longitudinal edges (37, 38) are perpendicular to the longitudinal edge (20, 21).