Disk cartridge with centered magnetic plate

A disk cartridge comprising:

• a casing formed of first and second halves, said first half having an access opening for allowing driving means to be communicated with an internal space of said disk cartridge and said second half having a first projecting portion projected from an inner surface of said second half which opposes said first half, along a predetermined circumference;
• a disk having an axial opening formed substantially in a center portion thereof and having a recess surrounding a periphery of said axial opening, said recess being formed to depend from one planar surface of the disk toward a second planar surface of the disk which is parallel to the first planar surface and having an annular bottom flange which surrounds the axial opening, said annular bottom flange having a chucking surface facing the exterior of said disk cartridge through said access opening and a counter chucking surface facing the internal space of said disk cartridge, said disk further having a second projecting portion projected along a circumference of said recess toward said second half of said casing;
• a magnetic plate provided in said recess, a height of said magnetic plate being greater than a shortest axial distance between said disk and an inner surface of said second half of said casing which opposes the recess.