When a long illuminant module is constructed, debonding of a bonded interface or bending occurs due to a difference in a magnitude of thermal deformation between a lens material and a metal substrate. In an illuminant module including light emitting elements, a substrate on which the light emitting elements are mounted, a transparent encapsulating resin which encapsulates the light emitting elements, and a lens material having cavities formed therein, in which the respective light emitting elements and transparent encapsulating resin are stored, notches are formed in a surface of the lens material on the side of the substrate, and the notch surfaces of the notches and the surface of the substrate are bonded using a bonding material.