A battery mounting mechanism includes a terminal connector, a first stopper, a second stopper, and a release button. The first stopper is disposed movably in the Z axis direction with respect to the terminal connector. The second stopper is disposed on the opposite side of the terminal connector with respect to the first stopper, and is disposed movably in the Z axis direction with respect to the terminal connector. The release button is arranged to release the restriction of the first battery or the restriction of the second battery by the first stopper, and arranged to drive the first stopper and the second stopper in the Z axis direction with respect to the terminal connector.