In a magnetic tape cartridge comprising a thin cartridge casing having flat
upper and lower surfaces and a single reel which is housed in the
cartridge casing for rotation and around which a magnetic tape is wound,
island-like or point-like projections are provided at least three places
of the lower surfaces of the cartridge casing near the leading edge and
the trailing edge of the cartridge casing as viewed in the direction X of
insertion of the magnetic tape cartridge in a recording and reproducing
apparatus and recesses which are adapted to be engaged with the
projections are provided on the upper surface of the cartridge casing so
that, when a plurality of the magnetic tape cartridges are stacked, the
projections and the recesses of the cartridge casings of magnetic tape
cartridges which are just above and below each other are engaged with each
other, whereby the magnetic tape cartridges are prevented from being
displaced with respect to each other when a plurality of magnetic tape
cartridges are stacked and the sliding resistance when the magnetic tape
cartridge is inserted into a recording and reproducing apparatus is
reduced.
