A channel fastener for fastening an object to an elongate channel element having an elongate slot flanked by flanges includes an assembly of a rigid washer element, an oblong metal anchoring element and a support for the anchoring element, which support is connected to the washer element and carries the anchoring element. The support includes a head portion coupled to the washer element, a bottom portion supporting the anchoring element from below, and connecting legs, extend along a longitudinal side of the anchoring element from the head portion to the bottom portion. The head portion and the connecting legs of the support form a tapering width from the head portion towards the bottom portion of the support. At least the head portion at the location where it adjoins the legs has an initial width that exceeds the width of the longitudinal slot.