A battery mounting structure has a battery that is placed in a luggage space and that has a positive electric power terminal which protrudes upward near a rear end of the battery, a battery cover that covers at least a part of the battery, a rear pillar that is placed at a boundary between a side surface and a back surface of the vehicle and that has a flange which protrudes to a front side, and an insulating sheet that is attached to the battery cover so as to be positioned between the positive electric power terminal and the flange.