Method of manufacturing light emitting element mounting base member, method of manufacturing light emitting device using the light emitting element mounting base member, light emitting element mounting base member, and light emitting device using the light emitting element mounting base member

A light emitting element mounting base member comprising:

• a plurality of electrical conductor cores;
• a plurality of light-reflecting insulating members, each of which covers lateral surface of each of the electrical conductor cores;
• and
• a light blocking resin that joins the at least two insulating members,
• wherein at least one upper surface of the electrical conductor cores, at least one lower surface of the electrical conductor cores, and the at least one insulating member around the upper surfaces and the lower surfaces of the electrical conductor cores are exposed from the light blocking resin respectively.