A battery pack includes: a battery having a main surface; and a resin layer capable of being integrated with an armor member armoring the battery so that at least a part of the main surface of the battery is exposed and covering the main surface of the battery, wherein the resin layer is formed by curing a reaction curable resin having a viscosity of not less than 80 mPa·second to less than 1000 mPa·second and a thickness of the resin layer on the main surface of the battery ranges from 0.05 mm to smaller than 0.4 mm.