To prevent wrinkles and air bubbles or the like from being generated, and reduce labor by combining a lid, on which a label is affixed, with a case, and performing an affixing motion wherein the remaining section of the label is continuously affixed to the side surface and the front surface of the case.

In order to build up a battery pack 1, a lid 5, on which one section of a label 6 is affixed, is positioned under a state wherein at specified locations in a case 2, a secondary battery 4 and a wiring material 3 are fixed, then, the case 2 and the lid are combined with each other. Then, the lid 5 is fixed to the case 2 by bonding the lid 5, on which one section of the label 6 is affixed, to the secondary battery 4. At the same time when the inside of the case 2 is packed, the case 2 and the lid 5 are integrated, and a semi- completed product 7 is formed. The other section of the label 6 is affixed to the case 2, and thus, the battery pack 1 is completed. By this constitution, wrinkles and air bubbles or the like are prevented from being generated, and labor can be reduced.