To facilitate battery mounting work, and surely fix a battery in a stable condition.

In a battery mounting structure for an automobile carrying in a battery carrier 20 pre-storing a battery mounted on a battery placing part 11 of a battery mounting part 10 closing one side by a partition 3 to be formed with a battery carry-in port 14 opposed to the partition 3, a battery loading guide rail 15 is provided in an upper surface of the battery placing part 11, and a fitting rail 22 is provided in a bottom surface of the battery carrier 20. The structure has a first lock part 30 locking the battery carrier 20 to the partition 3 by operation of an operating handle 38 arranged in the vicinity of the battery carry-in port 14 and a second lock part locking the battery carrier 20 to the battery placing part 11 in the vicinity of the battery carry-in port 14.