This aims to provide a pulse laser welding aluminum alloy material, which can prevent the occurrence of an abnormal portion, when an A1000-series aluminum material is welded with a pulse laser, so that a satisfactory welded portion can be homogeneously formed, and a battery case. The pulse laser welding aluminum alloy material is made of an A1000-series aluminum material, and has a viscosity of 0.0016 Pa·s or less in a liquid phase. Alternatively, the pulse laser welding aluminum alloy material has such a porosity generation rate of 1.5 (µm 2 /mm) or less in the pulse-laser welded portion as is numerically defined by dividing the porosity total area (µm 2 ), as indicated by the product of the sectional area and the number of porosities, by the length (mm) of an observation section.