The invention relates to a mobile concrete pump comprising a supporting structure (46) that is placed directly or indirectly by means of an assembly frame (22) on the running gear (12) of an HGV chassis (10), the supporting structure incorporating functional units that form a support device and a placing boom (36). The placing boom (36) is rotatably mounted on a boom pedestal (44). The boom pedestal (44) comprises a vessel (52) that is inserted in the supporting structure (46) and acts as a rotary bearing for the placing boom (36), while the support device has two support leg casings (54, 56) which are integrated into the supporting structure (46), cross over one another, have diagonal passages that are open at the front and have a telescopic support leg (40) in each support leg casing. A feature of the invention is that the supporting structure (46) has a polygonal opening (50) which is open at the top and runs parallel to the rotational axis (48) of the placing boom (36), while the contour of the vessel (52) of the boom pedestal (44) is adapted to the polygonal opening (50) and the vessel is inserted from above into the polygonal opening (50) of the supporting structure (46). To achieve a particularly favorable flow of forces in this construction between the placing boom (36) and the support legs (40), each of two lateral faces (68) of the vessel (52) which form an angle to one another is aligned parallel with a respective lateral wall (70) of each support leg casing (54, 56).