An optical disc apparatus includes a memory, a control circuit, a motor, a
spindle, and a pickup head. When determining the type of optical disc,
the optical disc apparatus moves a focusing lens at a constant velocity.
A first duration is measured that indicates how much time it takes for
the moving focal point of a laser shining through the focusing lens to
pass through a first layer of the optical disc. A second duration is also
measured that indicates how much time it takes for the moving focal point
to move from the first layer to a second layer of the optical disc. A
ratio of the second duration to the first duration indicates optical disc
type.