Abstract: A battery unit arrangement structure for a vehicle increases legroom for a passenger while disposing a battery in front of the passenger seat. The structure includes a dash vertical wall separating an interior from an engine compartment, a floor panel of the interior, and a curved corner portion connecting the lower end of the dash vertical wall and the front end of the floor panel together. The battery unit is mounted on the corner portion in front of the passenger seat with the upper surface of the battery unit inclined downward toward the vehicle rear so the rear end of the battery unit is lower than the front end of the battery unit. The battery unit is covered from above with a cover member inclined downward toward the vehicle rear so the rear end of the cover member is lower than the front end of the cover member.