A battery pack comprising: a case having an intake port for introducing air into an interior space thereof and an exhaust port for exhausting air from the interior space; and a plurality of battery accommodation sections (7a, 7b, 7c) arranged along a first direction within the interior space of the case and respectively accommodating a plurality of battery cells with clearances therebetween, wherein the clearances allowing air to pass therethrough in a second direction, the second direction intersecting with the first direction, characterized by further comprising: a plurality of supply flow paths (9a, 9b, 9c) provided at one end of the second direction of each of the battery accommodation sections, exhaust flow paths (10a, 10b, 10c) provided at the other end of the second direction of the battery accommodation sections and communicated with the exhaust port; a guide disposed on an inner surface of the case and elongated along the first direction; and a distribution flow path defined by the guide and the inner surface of the case, elongated along the first direction, and communicated with the intake port and the plurality of supply flow paths (9a, 9b, 9c), wherein the guide is provided so that a section area of the distribution flow path gradually decreases with increasing distance from the intake port, and wherein said distribution flow path defined by the guide and the inner surface of the case is positioned above the battery cells, and the guide functions to prevent that air, supplied from the intake port, flows to the exhaust flow paths via the area above the battery cells. a case having an intake port for introducing air into an interior space thereof and an exhaust port for exhausting air from the interior space; and a plurality of battery accommodation sections (7a, 7b, 7c) arranged along a first direction within the interior space of the case and respectively accommodating a plurality of battery cells with clearances therebetween, wherein the clearances allowing air to pass therethrough in a second direction, the second direction intersecting with the first direction, characterized by further comprising: a plurality of supply flow paths (9a, 9b, 9c) provided at one end of the second direction of each of the battery accommodation sections, exhaust flow paths (10a, 10b, 10c) provided at the other end of the second direction of the battery accommodation sections and communicated with the exhaust port; a guide disposed on an inner surface of the case and elongated along the first direction; and a distribution flow path defined by the guide and the inner surface of the case, elongated along the first direction, and communicated with the intake port and the plurality of supply flow paths (9a, 9b, 9c), a plurality of supply flow paths (9a, 9b, 9c) provided at one end of the second direction of each of the battery accommodation sections, exhaust flow paths (10a, 10b, 10c) provided at the other end of the second direction of the battery accommodation sections and communicated with the exhaust port; a guide disposed on an inner surface of the case and elongated along the first direction; and a distribution flow path defined by the guide and the inner surface of the case, elongated along the first direction, and communicated with the intake port and the plurality of supply flow paths (9a, 9b, 9c), wherein the guide is provided so that a section area of the distribution flow path gradually decreases with increasing distance from the intake port, and wherein said distribution flow path defined by the guide and the inner surface of the case is positioned above the battery cells, and the guide functions to prevent that air, supplied from the intake port, flows to the exhaust flow paths via the area above the battery cells.