A battery pack comprising: a battery module group that includes a plurality of battery modules including a plurality of battery bodies which include one battery cell or a plurality of the battery cells connected to each other in parallel, which are provided to be erected in a height direction in which a positive electrode and a negative electrode are opposite to each other, and which are arranged in an even number in a first direction orthogonal to the height direction, and bus bars for battery bodies which connect the battery bodies adjacent to each other in the first direction in series, and bus bars for modules which connect the battery modules, which are adjacent to each other in a second direction among the plurality of battery modules arranged in the second direction orthogonal to the first direction, in series; heat conductive members that have heat conductivity, and are provided between the plurality of battery modules which are arranged in the first direction and adjacent to each other in the second direction; and a heat dissipation unit that dissipates heat conducted to the heat conductive members, wherein the bus bars for modules are provided on one side of the battery modules in the height direction, the heat conductive members include contact portions that are in contact with the plurality of battery modules which are arranged in the first direction and adjacent to each other in the second direction, and extended portions that extend from a side opposite to the bus bars for modules of the battery modules in the height direction and are connected to the heat dissipation unit, and each of the bus bars for modules includes a first bus bar for modules which is provided in a battery module on one side between the battery modules adjacent to each other, a second bus bar for modules which is provided in the battery module on the other side and is different from the first bus bar for modules, and a connection portion that connects the first bus bar for modules and the second bus bar for modules. a battery module group that includes a plurality of battery modules including a plurality of battery bodies which include one battery cell or a plurality of the battery cells connected to each other in parallel, which are provided to be erected in a height direction in which a positive electrode and a negative electrode are opposite to each other, and which are arranged in an even number in a first direction orthogonal to the height direction, and bus bars for battery bodies which connect the battery bodies adjacent to each other in the first direction in series, and bus bars for modules which connect the battery modules, which are adjacent to each other in a second direction among the plurality of battery modules arranged in the second direction orthogonal to the first direction, in series; heat conductive members that have heat conductivity, and are provided between the plurality of battery modules which are arranged in the first direction and adjacent to each other in the second direction; and a heat dissipation unit that dissipates heat conducted to the heat conductive members, wherein the bus bars for modules are provided on one side of the battery modules in the height direction, the heat conductive members include contact portions that are in contact with the plurality of battery modules which are arranged in the first direction and adjacent to each other in the second direction, and extended portions that extend from a side opposite to the bus bars for modules of the battery modules in the height direction and are connected to the heat dissipation unit, and each of the bus bars for modules includes a first bus bar for modules which is provided in a battery module on one side between the battery modules adjacent to each other, a second bus bar for modules which is provided in the battery module on the other side and is different from the first bus bar for modules, and a connection portion that connects the first bus bar for modules and the second bus bar for modules.