To easily adjust the relative position between lenses with high accuracy and to suppress generation of spherical aberration in an objective lens composed of a plurality of lenses and having ≥0.7 numerical aperture.

The manufacturing device is equipped with a positioning mechanism 31 in which one lens 1 is attached and fixed to a cylindrical lens holder 3 made of a synthetic resin material and another lens 2 is positioned with respect to the first lens 1 as the reference and is fixed to the lens holder 3 so as to relatively position the lenses 1, 2.