A case with a partitioning member in which the welding between a case and a cover and between the case and the partitioning member can be confirmed by an airtightness test. The case with a partitioning member includes a cover and a partitioning member held between the case and the cover. On the inside of a first welding portion in which the case and cover are welded to each other, a second welding portion in which the case and partitioning member are welded to each other is provided, and on the inside of the second welding portion, a third welding portion in which the case and the partitioning member are welded to each other is provided. Holes open to the atmosphere are provided in the case between second and third welding portions.