A laser converging apparatus is disclosed that comprises a polarizing
hologram element having a first area defined by a numerical aperture
corresponding to a thickness of a first protective layer of a first disk
medium and a second area inside the first area, the second area defined
by a numerical aperture corresponding to a thickness of a second
protective layer (> the thickness of the first protective layer) of a
second disk medium, the second area having a hologram pattern for
transmitting first laser light linearly polarized in a first direction
without diffracting the first laser light while diffracting and
transmitting second laser light that is linearly polarized in a second
direction crossing the first direction at right angles, the second laser
light having the same wavelength as the first laser light; an objective
lens having the numerical aperture corresponding to the thickness of the
first protective layer, the objective lens converging the first laser
light having passed through the first area including the second area onto
an information surface on one side of the first protective layer, the
objective lens converging the second laser light having passed through
the second area onto an information surface on one side of the second
protective layer; and a holder that holds the polarizing hologram element
and the objective lens.