A battery module includes a pair of secondary batteries disposed adjacent to each other and a spacer disposed between the secondary batteries. Each of the secondary batteries includes a plurality of electrodes each of which has a rectangular shape and is disposed to face each other, a case configured to house the electrodes, the case having a rectangular parallelepiped shape, and an electrolyte in the case. The spacer is made of an elastic body. An aspect ratio of each of the electrodes is 10 or less, and a spring constant of the spacer is 0.03 MPa/mm or more and 5.4 MPa/mm or less.