Abstract: A mounting device (1) for fastening at least one plumbing appliance comprises two supports (2) which extend at a distance from each other along a central axis (M), and a transverse element (3) which is placed between the supports (2), connects the two supports (2) and includes at least one fastening element (4), the transverse element (3) being formed by a front supporting piece (5) with a supporting wall (6) on which a plumbing appliance can be supported, and a rear supporting piece (7) with a rear wall (8), the front supporting piece (5) and/or the rear supporting piece (7) being provided with at least one connection flange (9, 10) which projects at a right angle from the supporting wall (6) and/or from the rear wall (8) and which allows the two supporting pieces (5, 6) to be fixedly connected to one another such that in the connected state, the supporting wall (6) is at a distance from the rear wall (8).