A method of testing a battery includes the following steps. Step A1 is a step of preparing a test target battery. Step A2 is a step of measuring magnetism when applying an electric current to the test target battery. Step A3 is a step of obtaining a current distribution of the test target battery based on the magnetism measured in step A2. Step A4 is a step of comparing the current distribution of the test target battery obtained in step A3 with a normal current distribution that is obtained in advance, with predetermined reference positions being aligned with each other.