Magnetic disc cartridge with protrusion opposing disc entirely outside recording area thereof

A magnetic disc cartridge comprising a casing formed by upper and lower shells bonded together, a magnetic disc which is supported for rotation about an axis in the casing and includes a recording area and a non-recording area around the recording area, and a pair of liners fixed respectively to the inner surfaces of the upper and lower shells to be opposed to the upper and lower surfaces of the disc, wherein the improvement comprises that

• each of the upper and lower shells is provided with at least one protrusion extending longitudinally inward generally toward the axis, and projecting toward the disc from the inner surface which is entirely outside the portion of the shell opposed to the recording area of the magnetic disc and is opposed to at least a part of the non-recording area of the magnetic disc, whereby the liners of the respective shells are shifted toward the disc from the inner surfaces of the shells by the protrusions.