A Coriolis mass flow measuring device and/or density measuring device includes two bent measuring tubes, which extend mirror symmetrically to a first mirror plane between the measuring tubes, an actuator arrangement and at least one sensor arrangement. At the inlet end and at the outlet end, a collector, with which the measuring tubes are joined, wherein the collectors each fulfill the functionality of a node plate. A support body, which connects the collectors rigidly with one another; and inlet end and outlet end, in each case, at least one plate-shaped coupler, which connect the measuring tubes pairwise with one another, in order to form an oscillator. The couplers have tube openings for measuring tubes, wherein the measuring tubes are connected at least sectionally with the couplers, wherein inlet end and outlet end, in each case, at least one coupler has, between the measuring tubes, a tuning opening for influencing the oscillation characteristics of the oscillator.