The present invention refers to an apparatus for rotationally fixing a seal ring (4) of a mechanical seal assembly retained at a mounting component (1) to be axially movable, comprising a force transmitting ring (10) retained at the mounting component to be axially movable and a rotation prevention device comprising at least one first engaging member (17) configured to engage with the mounting component and the force transmitting ring in a form-fit manner and at least one second engaging member (18) configured to engage with the force transmitting ring and the seal ring in a form-fit manner, the first engaging member being arranged circumferentially offset with respect to the second engaging member, characterized in that the engaging members (17, 18) protrude axially from the force transmitting ring (10) or the seal ring (4) toward the respectively other component (seal ring or force transmitting ring) and are configured to be received in axial recesses (19, 20) provided in the respectively other component with a play.