An anchor element serves for knotless fixing of a tissue to a bone by at least one suture threaded through the anchor element. A body of that anchor element has an outer surface with projections. A transverse bore is arranged in a distal end section of the body for receiving a threading passing therethrough. A clamp element serves for clamping the suture threaded transversely through the bore. The clamping element has a portion arranged within the body and is movable within the body towards that transverse bore.