A plastic one-piece molding fastener for an elongated object includes a holding portion for holding an elongated object, first and second leg portions depending from the holding portion, first and second elastic locking portions extending from the ends of the respective first and second leg portions toward the bottom of the holding portion so as to define therewith substantially U-shaped members, locking shoulders provided on the first and second elastic locking portions for being engaged with the edge and undersurface of a mounting hole of a mounting plate within which the elongated object is to be secured, and first and second lever portions extending in opposite directions from upper portions of the elastic locking portions and perpendicular to the axial direction of the fastened elongated object and inclined downwardly with respect to the bottom of the holding portion. The first and second leg portions are serially arranged or aligned in the axial direction of the fastened elongated object and are staggered with respect to each other in a perpendicular direction with respect to the axial direction of the fastened elongated object. The first and second elastic locking portions project outwardly in directions perpendicular to the axial direction of the fastened elongated object and are disposed upon opposite sides of the longitudinal axis of the fastener.