A phosphorescent layer comprising a phosphorescent compound and a binder resin is provided at least on the front surface of a bulb in order to provide a lamp having phosphorescent layer with improved strength and durability and also an improved recognizability even after turning off the light. A portable lighting device having the lamp is also provided. A phosphorescent layer is applied to the front surface of a single-end bulb of a lamp in the range from 1/4 to 1/2 of the bulb surface area. The phosphorescent layer mainly comprises strontium aluminate (SrAl.sub.2 O.sub.4). This material is added to a solution dissolving a binder resin and mixed to provide a paint, and the paint is applied to a predetermined position of the lamp. For the application, the single-end bulb is dipped in the paint and dried to evaporate the solvent. The paint preferably comprises 1-50 weight parts of the binder resin to 100 weight parts of the phosphorescent compound.