A lamp with an outer bulb is provided. The outer bulb is attached to an attaching member of a base by simple and convenient fabrication, and reliably prevents detachment of the outer bulb from the attaching member. An outer peripheral surface of a supporting post formed to the attaching member of the base and an inner peripheral surface of the outer bulb define a gap therebetween that may receive a heat resistant adhesive or filler. Convex portions facing the gap may be formed to the outer peripheral surface of the supporting post and the inner peripheral surface of the outer bulb, respectively, and a joint body for joining the outer bulb and the supporting post is defined between the outer peripheral surface of the supporting post and the inner peripheral surface of the outer bulb by the adhesive or filler in the gap.