Abstract: A support device for supporting on a stationary framework a mass which is cantilevered-out from a moving element that moves under the effect of thermal expansion or contraction. The device comprises a rigid stand supporting the mass and connected to the stationary framework via two parallel arms of equal length and situated at two different heights, each of the two arms being hinged at one of its ends to a corresponding point on the stand and at its other end to a corresponding point on the stationary framework, the rigid support being placed on the moving elements via a connection that slides horizontally. The device is applicable to supporting collector manifolds in steam generators or boilers.