A Coriolis mass flow measuring device and/or density measuring device, comprising: at least two measuring tubes which extend mirror symmetrically to a first mirror plane; at least one exciter mechanism and at least one sensor arrangement for exciting and registering measuring tube oscillations; two terminally located collectors for joining the measuring tubes; a support body for connecting the collectors; and a number of plate-shaped couplers for pairwise connecting of the measuring tubes for forming an oscillator. The measuring tube centerlines of the measuring tubes have two oppositely bent sections and an intermediately lying straight section. The second bent section is arranged on the side of the straight section away from the second mirror plane. The projection of the measuring tube centerline between the intersection with the second mirror plane and the transition between the straight section and the second bent section onto the second mirror plane is not less than the separation between the second mirror plane and the measuring tube centerline at the transition between the straight section and the second bent section, wherein the first bent section has stiffening element, which annularly grip around the measuring tube.