To provide a method for manufacturing a reflective optical device in which a reflective LED can be surface mounted while exhibiting resistance against temperature variation, the size can be reduced easily, the degree of freedom of available sealing material is high, and excellent mass productivity is ensured.

Leads 3a and 3b mounting a light emitting element 2 are led out in one direction and fixed with a concave reflector 4 formed by pressing an aluminum plate and then sealed by potting mold using transparent epoxy resin 5. Resistance against temperature variation is attained using a metal reflector 4 and surface mounting can be carried out in a reflow furnace. Furthermore, the size can be reduced because a lead out part for preventing short circuit due to deposition is not required, and extremely excellent mass productivity is ensured because a potting mold can be produced easily and sealing can be performed at once by arranging a plurality of molds. In addition, the degree of freedom of available sealing material is high and a sealing resin not changing into yellow can be used, and the luminous intensity distribution characteristics can be altered by simply varying the shape of the reflective surface 4a of the reflector 4.