The present invention relates to a building material mixer having a mixer drum which can be rotationally driven by a mixer drive, with the mixer drum being rotatably supported by the mixer drive at a mixer frame part, in particular a traveling gear frame part, at one of its end face ends and with the mixer drive having a drive part, in particular a hydraulic motor, and a drive transmission connected to the mixer drum. In accordance with the invention, the building material mixer is characterized in that the mixer drive is movably supported by movable bearing means at the mixer frame part allowing tilting movements; and in that the mixer drum is fastened to the transmission housing of the drive transmission.