The object of the present invention is to provide a light-emitting element mounting member and a semiconductor device using the same that is easy to process and that allows adequate heat dissipation.A light-emitting element mounting member 200 includes: a substrate 2 including an element mounting surface 2a mounting a semiconductor light-emitting element 1 and first and second conductive regions 21, 22 disposed on the element mounting surface 2a and connected to the semiconductor light-emitting element 1; a reflective member 6 including a reflective surface 6a defining an internal space 6b for housing the semiconductor light-emitting element 1 and containing a metal disposed on the element mounting surface 1a; and a metal layer 13 disposed on the reflective surface 6a. The reflective surface 6a is sloped relative to the element mounting surface 2a so that a diameter of the internal space 6b is greater away from the element mounting surface 2a.