A battery pack including: • a pack body having a first main surface and a second main surface that are opposed to each other in a first axis direction, • a first end surface and a second end surface that are opposed to each other in a second axis direction orthogonal to the first axis direction, • a first side surface and a second side surface that are opposed to each other in a third axis direction orthogonal to the first axis direction and to the second axis direction; and • a first concave portion and a second concave portion provided on the first end surface, wherein at least a part of the first concave portion and at least a part of the second concave portion are open along the third axis, • wherein the first end surface is provided between the first main surface and the second main surface and includes a first terminal window exposing a positive terminal, a second terminal window exposing a negative terminal and a third terminal window exposing a temperature detection terminal, the temperature detection terminal placed in between the positive terminal and the negative terminal, • wherein the terminal windows (42a-c) are arranged on the first end surface and closer to the first side surface than the second side surface, and the first concave portion and the second concave portion are closer to the second main surface than a centre line passing the center of the first end surface and being parallel to the third axis, so that there is, in a direction perpendicular to the centre line, a gap between an edge of each terminal window (42a, 42b, 42c) and an edge of each concave portion (43, 44). • a pack body having a first main surface and a second main surface that are opposed to each other in a first axis direction, • a first end surface and a second end surface that are opposed to each other in a second axis direction orthogonal to the first axis direction, • a first side surface and a second side surface that are opposed to each other in a third axis direction orthogonal to the first axis direction and to the second axis direction; and • a first concave portion and a second concave portion provided on the first end surface, wherein at least a part of the first concave portion and at least a part of the second concave portion are open along the third axis, • wherein the first end surface is provided between the first main surface and the second main surface and includes a first terminal window exposing a positive terminal, a second terminal window exposing a negative terminal and a third terminal window exposing a temperature detection terminal, the temperature detection terminal placed in between the positive terminal and the negative terminal, • wherein the terminal windows (42a-c) are arranged on the first end surface and closer to the first side surface than the second side surface, and the first concave portion and the second concave portion are closer to the second main surface than a centre line passing the center of the first end surface and being parallel to the third axis, so that there is, in a direction perpendicular to the centre line, a gap between an edge of each terminal window (42a, 42b, 42c) and an edge of each concave portion (43, 44).