Lens holder having an adjustment groove of a taper shape

An optical pickup unit comprising a lens holder installed in an optical base with a lens fitted therein, said optical base comprising a base plate and a vertical wall perpendicularly extending upwards from said base plate, said lens holder being always pressed against a corner portion formed by said base plate and said vertical wall by a presser bar spring, said lens holder having an adjustment groove formed therein, said adjustment groove having a taper shape where a width thereof becomes narrower in proportion to near to said vertical wall and the width thereof becomes wider in proportion to apart from said vertical wall extending in a direction perpendicular to said vertical wall, thereby adjusting a position of said lens by making said lens holder move along an optical axis of a laser beam by moving an adjustment pin through a hole formed in said base plate with said adjustment pin inserted in said adjustment groove.