The purpose of the present invention is to provide an illumination light source that has favorable light distribution properties and is simple to assemble. An illumination light source (1) having one or a plurality of light-emitting modules (10) which serve as light sources accommodated in an outer enclosure (2) constituted by a cylindrical case (60) having an opening at the top, which is the illumination direction, and a globe (30) mounted above the case (60) so as to close the opening, wherein all of the light-emitting modules (10) within the outer enclosure (2) are disposed flat with the primary emission direction directed upwards; above the light-emitting modules (10) one or a plurality of optical members (80) for diffusing emitted light from the light-emitting modules (10) are disposed so that the emitted light attains a maximum luminosity at an emission angle in the range of 30° to 60° when it reaches an inner surface (32) of the globe (30).
