A magnetic disk device configured such that a carriage having an arm on one end
and a coil on the other end is pivotally supported rotatably on a chassis, the
arm having a magnetic head on its tip, the other end of the carriage loaded with
the coil is placed in a magnetic circuit having a magnet the carriage is rotated
around an axis core by driving force generated on the coil, and the tip of the
arm having the magnetic head is moved over a magnetic disk and a retreat position
on a ramp. In such a device, magnetized protrusion is provided on the proximal
end of the arm.
