Abstract: To provide a battery pack that can be thinned without causing an interference with other members such as a pointing device and reducing a capacity, an electronic apparatus equipped with the battery pack, and a battery pack mounting method. [Solving Means] A battery pack (9) includes first casing portions (45a, 45b) incorporating secondary batteries (52a, 52b) and a second casing portion {46) incorporating a control board (53) and a wiring sheet metal (54). The thickness of the second casing portion (46) is smaller than that of the first casing portions (45a, 45b). Accordingly, by increasing the areas of the first casing portions (45a, 45b) when thinning the battery pack (9), for example, it is possible to incorporate the secondary batteries (52a, 52b) having large areas and prevent the capacity from becoming smaller. In addition, by appropriately setting the arrangement position of the second casing portion (46) having a small thickness, the battery pack (9) can be mounted to an electronic apparatus without causing an interference with other members such as a pointing device. [Selected Drawing] Fig. 9
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