A multi-beam luminous source apparatus, an optical scanning apparatus, and an image formation apparatus are disclosed. The multi-beam luminous source includes a first member for supporting a coupling lens and a second member for supporting a control substrate that supports a Vertical Cavity Surface Emitting Laser (VCSEL). The first member and the second member are joined with a screw at a reference plane that perpendicularly intersects an optical axis of the coupling lens. The second member includes a base member A for supporting the control substrate and a base member B that includes a branch mirror, a convergent lens, and an optical detection sensor.