This disclosure relates to a truck-mounted concrete pump including a vehicle, a concrete distributor boom disposed on the vehicle and including multiple boom arms that can be stowed, in the form of an arm assembly, on a vehicle-mounted boom resting unit, and a boom hydraulic system configured to stow and unfold the arm assembly and including a hydraulic cylinder that moves the arm assembly against the boom resting unit in a stowing movement. To terminate the boom stowing movement, a protective circuit is coupled to the hydraulic cylinder. The protective circuit includes a switching unit actuable under the load of the arm assembly. The switching unit has a load receiving element arranged on the boom resting unit that is resiliently deformable when stowing the arm assembly, wherein the arm assembly is only supported on the boom resting unit by the load receiving element.