Abstract: An apparatus for mixing the content of a closed package, such as a paint can. The apparatus comprises a frame and a substantially vertically oriented package holder which is movably mounted in the frame. The package holder includes a device for releasably clamping a package so that the axis of the package is parallel with the axis of the holder. The apparatus also includes a device for driving the holder in a closed movement path relative to the frame. The drive device comprises a rotatable shaft which is substantially vertically oriented and which is mounted centrally on the frame. The drive shaft carries a crank having a substantially vertical pin. The pin is centrally connected to the lower portion of the holder and is journalled at one of its ends into a rolling bearing. Stabilizing devices connect the holder and the frame and are arranged to prevent relative rotation between the holder and the frame around the drive shaft axis.