The present invention provides a battery module comprising: a plurality of battery cells of which the horizontal length of a front surface is formed to be longer than the vertical length and which are vertically stacked; a cooling fin which has a first cooling part contacting an upper and lower surface of adjacent battery cells, and a second cooling part extending from both side surfaces of the first cooling part and contacting both side surfaces of the battery cells which are in contact with the first cooling part; and a side cooling fin which has an ground part contacting a side surface of the second cooling part of the cooling fin, and contacting a heat sink located in a lower part.