Driving apparatus for an objective lens

An objective lens drive device comprising a base member having a support shaft extending therefrom, a lens holder member including a cylindrical side wall and an end wall extending across said side wall, said end wall having bearing means therein slidable axially on said support shaft, an objective lens mounted in said end wall for adjusting the focus of said objective lens in response to the axial sliding of said holder member along said shaft, a focusing coil wound circumferentially on the outer surface of said cylindrical side wall, and a magnetic circuit including a magnet, an inner yoke member extending from said base member within said cylindrical side wall and an outer yoke member arranged outside of said cylindrical side wall so that said focusing coil is situated in a magnetic gap of said magnetic circuit and causes said adjusting of the focus in response to a current flow through said focusing coil, said end wall of the lens holder member having an aperture opening therethrough and dimensioned and located to loosely receive a distal end of said inner yoke member and thereby avoid interference with relative movements of said end wall along said shaft in the direction toward said base member so that substantially the full axial dimension of said cylindrical side wall can accommodate said focusing coil for achieving sensitivity of said adjusting of the focus while minimizing the axial dimension of said lens holder member.