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 (X) direction, • a first end surface and a second end surface that are opposed to each other in a second axis (Y) direction orthogonal to the first axis (X) direction, • a first side surface and a second side surface that are opposed to each other in a third axis (Z) direction orthogonal to the first axis (X) direction and to the second axis (Y) 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 (Z), • 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 (P2) passing the center of the first end surface and being parallel to the third axis (Z), so that there is, in a direction perpendicular to the centre line (P2), a gap between an edge of each terminal window and an edge of each concave portion . • a pack body having a first main surface and a second main surface that are opposed to each other in a first axis (X) direction, • a first end surface and a second end surface that are opposed to each other in a second axis (Y) direction orthogonal to the first axis (X) direction, • a first side surface and a second side surface that are opposed to each other in a third axis (Z) direction orthogonal to the first axis (X) direction and to the second axis (Y) 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 (Z), • 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 (P2) passing the center of the first end surface and being parallel to the third axis (Z), so that there is, in a direction perpendicular to the centre line (P2), a gap between an edge of each terminal window and an edge of each concave portion . <EOS>