To provide a junction structure and a junction method for conductive projection advantageous in that a required reinforcement strength can be obtained while suppressing the amount of a reinforcing resin material supplied to prevent warpage due to curing shrinkage. A conductive projection is joined to the surface of a conductor portion formed at the same level as that of the surface of the insulating layer so that a root portion of the projection is surrounded by a fillet-form resin material. The resin material contains an activator which assists in the junction between the conductive projection and the conductor portion when the resin material is in an uncured state, and is fused by heating to wet and rise the root portion of the conductive projection so as to be in a fillet form. The resin material is cured by an ultraviolet light while excluding the resin material on the conductor portion.